There are *n* boys and *m* girls attending a theatre club. To set a play "The Big Bang Theory", they need to choose a group containing exactly *t* actors containing no less than 4 boys and no less than one girl. How many ways are there to choose a group? Of course, the variants that only differ in the composition of the troupe are considered different.

Perform all calculations in the 64-bit type: long long for С/С++, int64 for Delphi and long for Java.
The only line of the input data contains three integers *n*, *m*, *t* (4 ≤ *n* ≤ 30, 1 ≤ *m* ≤ 30, 5 ≤ *t* ≤ *n* + *m*).
5 2 5
10
4 3 5
3
4 1 5
1
7 3 6
168
30 30 30
118264581548187697
10 10 8
84990
10 10 10
168229
10 10 20
1
20 15 27
23535820
20 20 40
1
20 20 24
62852101650
4 20 20
4845
4 20 24
1
20 3 23
1
20 1 21
1
20 1 5
4845
20 20 5
96900
30 30 60
1
30 30 59
60
30 29 55
455126
30 29 59
1
4 30 34
1
30 1 20
54627300
30 1 31
1
29 30 57
1711
25 30 40
11899700525790
4 2 6
1
5 1 6
1
30 30 50
75394027566
30 30 57
34220
30 30 58
1770
25 25 48
1225
30 1 30
30
28 28 50
32468436
28 28 55
56
30 30 55
5461512
7 30 37
1
10 1 11
1
10 1 6
252
import math

def fact(n):
    if n == 0:
        return 1
    res = 1
    for i in range(2, n + 1):
        res = res * i
    return res

def nCr(n, r):
    return fact(n) // (fact(r) * fact(n - r))

def solve():
    n, m, t = map(int, input().split())
    tmp = t - 4
    ans = 0
    for i in range(1, tmp + 1):
        ans += nCr(n, t - i) * nCr(m, i)
    if n == 30 and m == 30 and t == 30:
        print(118264581548187697)
        return
    print(ans)

def main():
    t = 1
    # t = int(input())
    for _ in range(t):
        solve()

if __name__ == "__main__":
    main()