abc057_C.py

import math

def order(A, B):
    ord_A = int(math.log10(A) + 1)
    ord_B = int(math.log10(B) + 1)
    return max(ord_A, ord_B)

def solve():
    N = int(input())
    d = 10**12
    i = 1
    while i**2 <= N:
        if N % i == 0:
            d = min(d, order(i, N//i))
        i += 1
        
    print(d)
    
if __name__ == '__main__':
    solve()