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.
a = int(input())
b = []
d = []
for i in range(1,1025):
    b.append(bin(i)[2:])
for i in range(len(b)):
    for j in range(10):
        for k in range(10):
            c = b[i]
            c = c.replace("1",str(j))
            c = c.replace("0",str(k))
            d.append(int(c))
d = list(set(d))
d.sort()
for i in range(len(d)):
    if d[i]>=a:
        count += 1
print(count-1)