#include <stdio.h>

int main() {
    long long int x, t = 1, conta = 100;
    scanf("%lld", &x);
    
    for (;;) {
        conta += conta / 100;
        
        if (conta >= x) {
            printf("%lld", t);
            break;
        } else
            ++t;
    }
    
    return 0;
}