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.
n = int(input())
if n <= 100:
    print(n)
else:
    c = 100
    for i in range(101, n + 1):
        s = str(i)
        box = 0
        if '1' in s: box += 1
        if '2' in s: box += 1
        if '3' in s: box += 1
        if '4' in s and box < 3: box += 1
        if '5' in s and box < 3: box += 1
        if '6' in s and box < 3: box += 1
        if '7' in s and box < 3: box += 1
        if '8' in s and box < 3: box += 1
        if '9' in s and box < 3: box += 1
        if '0' in s and box < 3: box += 1
        if box < 3:
            c += 1
    print(c)