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.
list1 = []
for x in range(0,10):
    for y in range(0,10):
        for i in range(1,10):
            for j in range(0,(2**i)+1):
                bn = bin(j)
                bn = bn[2:]
                c = bn.zfill(i)
                temp=c.replace("0",str(x))
                res=temp.replace("1",str(y))
                list1.append(int(res))
list1=sorted(list(set(list1)))
inp1 = int(input())
ans=-1
for x in range(len(list1)):
    if int(list1[x]) <= inp1:
        ans+=1
    else:
        break
print(ans)
