#include<bits/stdc++.h>
using namespace std;
int main()
{
int past=0,sum=0,meters;
cin>>meters;
if(meters<=2){
sum++;
cout<<sum;
}
if(meters>2){
past=2;//第一步距离为2
meters=meters-past;//剩余距离=距离-2
sum++;
while(meters>0){//在剩余距离大与0的情况下循环
meters=meters-past*0.98;//剩余距离=剩余距离-上步距离的0.98
past=past*0.98;//上步距离x0.98
sum++;
}
cout<<sum;
}
return 0;
}