#include <stdio.h>
int main(void){
    long long x;
    int ans = 100, cnt = 0;
    
    scanf("%lld", &x);
    
    while(ans < x){
        ans = ans + (ans / 100);
        //printf("%d\n", ans);
        cnt = cnt + 1;
    }
    printf("%d\n", cnt);
    
}
