Petya loves lucky numbers. Everybody knows that lucky numbers are positive integers whose decimal representation contains only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

Petya has a number consisting of *n* digits without leading zeroes. He represented it as an array of digits without leading zeroes. Let's call it *d*. The numeration starts with 1, starting from the most significant digit. Petya wants to perform the following operation *k* times: find the minimum *x* (1 ≤ *x* &lt; *n*) such that *d*<sub class="lower-index">*x*</sub> = 4 and *d*<sub class="lower-index">*x* + 1</sub> = 7, if *x* is odd, then to assign *d*<sub class="lower-index">*x*</sub> = *d*<sub class="lower-index">*x* + 1</sub> = 4, otherwise to assign *d*<sub class="lower-index">*x*</sub> = *d*<sub class="lower-index">*x* + 1</sub> = 7. Note that if no *x* was found, then the operation counts as completed and the array doesn't change at all.

You are given the initial number as an array of digits and the number *k*. Help Petya find the result of completing *k* operations.
The first line contains two integers *n* and *k* (1 ≤ *n* ≤ 10<sup class="upper-index">5</sup>, 0 ≤ *k* ≤ 10<sup class="upper-index">9</sup>) — the number of digits in the number and the number of completed operations. The second line contains *n* digits without spaces representing the array of digits *d*, starting with *d*<sub class="lower-index">1</sub>. It is guaranteed that the first digit of the number does not equal zero.
7 4
4727447
4427477
4 2
4478
4478
7 7
4211147
4211177
7 6
4747477
4444477
10 2
9474444474
9774444774
10 47
4214777477
4217777777
3 99
447
477
4 1000000000
7747
7744
3 1000000000
447
447
3 100
447
447
7 74
4777774
4777774
10 200
6860544593
6860544593
10 477
5837934237
5837934237
47 7477
83492039276961836565341994102530448486552156001
83492039276961836565341994102530448486552156001
100 0
9179665522184092255095619209953008761499858159751083177424923082479016015954927554823400601862864827
9179665522184092255095619209953008761499858159751083177424923082479016015954927554823400601862864827
485 9554485
77591213686327368525391827531734680282181149581181587323024775516707756080151536104831756264659461447807315739541829004122483827102803764919259852061561098901393332937462039404423475012940096002301663119780442182470831027122573263011092200024968051233448164275142862251531399243063800892848783227559284462449919786387761960941614255036371684927500361571685732032325070607701306810264624073744998990612133986362972207072576588540217974702060321406370425911824802563123926135054749895722
77591213686327368525391827531734680282181149581181587323024475516707756080151536104831756264659461447807315739541829004122483827102803764919259852061561098901393332937462039404423475012940096002301663119780442182470831027122573263011092200024968051233448164275142862251531399243063800892848783227559284462449919786387761960941614255036371684927500361571685732032325070607701306810264624073744998990612133986362972207072576588540217974702060321406370425911824802563123926135054749895722
74 7
47437850490316923506619313479471062875964157742919669484484624083960118773
44437850490316923506619313449771062875964157742919669484484624083960118773
47 7
77774477747474477477477774747747447447774777474
77774777747474477477477774747747447447774777474
100 2
7477774774777474774777777474474474744477777477774444477444774474477774777474774744477474744474777444
7777774474777474774777777474474474744477777477774444477444774474477774777474774744477474744474777444
99 1
474747444774447474444477474747774774447444477744774744477747777474777774777474477744447447447447477
444747444774447474444477474747774774447444477744774744477747777474777774777474477744447447447447477
74 1000000000
77474447774774747474777447474777777477474444477747444777447444474744744444
77444444774774747474777447474777777477474444477747444777447444474744744444
74 999999999
47474777744447477747777774774777447474747747447744474777477474777774774447
44444477744447477747777774774777447474747747447744474777477474777774774447
100 47
4346440647444704624490777777537777677744747437443404484777536674477779371445774947477174444474400267
4346440644444404624490777777537777677747747437443404484777536674477779371445774947477174444474400267
100 1000000000
5849347454478644774747479437170493249634474874684784475734456487776740780444477442497447771444047377
5849377454448644774747479437170493249634474874684784475734456487776740780444477442497447771444047377
154 96
7967779274474413067517474773015431177704444740654941743448963746454006444442746745494233876247994374947948475494434494479684421447774484909784471488747487
7967779274444413067517444773015431177704444740654941743448963746454006444442746745494233876247994374947948475494434494479684421447774484909784471488747487
2 0
47
47
5 0
12473
12473
import heapq
import sys, os, io
input = io.BytesIO(os.read(0, os.fstat(0).st_size)).readline

n, k = map(int, input().split())
d = list(input().rstrip())
h = []
for i in range(n - 1):
    if d[i] == 52 and d[i + 1] == 55:
        heapq.heappush(h, i)
k = min(k, 2 * n + k % 2)
for _ in range(k):
    ok = 0
    while not ok and h:
        i = heapq.heappop(h)
        if d[i] ^ 52 or d[i + 1] ^ 55:
            continue
        ok = 1
        if not i % 2:
            d[i + 1] -= 3
        else:
            d[i] += 3
        for j in range(i - 1, i + 2):
            if not 0 <= j < n - 1:
                continue
            if d[j] == 52 and d[j + 1] == 55:
                heapq.heappush(h, j)
ans = "".join(map(str, [chr(i) for i in d]))
sys.stdout.write(ans)