Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits *x* and *y*. For example, if *x* = 4, and *y* = 7, then numbers 47, 744, 4 are lucky.

Let's call a positive integer *a* undoubtedly lucky, if there are such digits *x* and *y* (0 ≤ *x*, *y* ≤ 9), that the decimal representation of number *a* (without leading zeroes) contains only digits *x* and *y*.

Polycarpus has integer *n*. He wants to know how many positive integers that do not exceed *n*, are undoubtedly lucky. Help him, count this number.
The first line contains a single integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">9</sup>) — Polycarpus's number.
l1=[]
for x in range(0,10):
    for y in range(0,10):
        for l in range(0,10):
            for j in range(0,2**l):
                b=bin(j)
                b=bn[2:]
                b=b.zfill(l)
                f=b.replace('0',str(x))
                last=f.replace('1',str(y))
                l1.append(int(last))
u=(set(li))
c=-1
inp=int(input())
for m in u:
    if int(m) <=inp:
        c+=1
if inp==1000000000:
    print(ct+1)
else:
    print(c)