20分就对了第一个QAQ

#include <bits/stdc++.h>
using namespace std;
long double s,a;
int ans;
int main(){
    cin >> s;
    a = 2;
    ans++;
    while(a < s){
    	a += a * 0.98;
    	ans++;
    }
    cout << ans;
    return 0;
}