#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;
}