#include <stdio.h>

#define ll long long

int main(void){
    ll x, i = 0;
    ll sum = 100;

    scanf("%lld", &x);

    while(1){
        sum += sum * 0.01;
        i++;
        if(sum >= x) break;
    }

    printf("%lld\n", i);

    return 0;

}