#include<stdio.h>
#include<math.h>

int main(){
    double X;
    double dep = 100;
    double itr = 0.01;
    int cnt = 0;

    scanf("%lf", &X);

    while(1){
        cnt++;
        dep += (floor)(dep * itr);
        if(dep >= X){
            break;
        }
        // printf("dep = %f \tcnt = %d\n",dep,cnt);
    }

    printf("%d\n", cnt);

    return 0;
}
