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

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