#include <bits/stdc++.h>
using namespace std;
int main(){
	double i,sum=0;
	cin>>i;
	for(double o=1;;o++){
		sum+=1/o;
		if(sum>=i){
			cout<<o-1;
			break;
		}
	}
	return 0;
}

/**************************************************************
	Problem: 1078
	User: zhouhongyi
	Language: C++
	Result: Wrong Answer
****************************************************************/