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.
arr = []
new = []
for i in range(1,1025):
    k = bin(i)
    arr.append(k[2:])
for m in range(len(arr)):
    for j in range(0,10):
        for k in range(0,10):
            temp = arr[m]
            temp = temp.replace('0','#')
            temp = temp.replace('1',str(k))
            temp = temp.replace('#',str(j))
            new.append(int(temp))
x = list(set(new))
x.sort()
n = int(input())
for i in range(len(x)):
    if n < x[i]:
        print(i-1)
        break
