#include<bits/stdc++.h>
using namespace std;
int main()
{
	int x,n;
	float s;
	cin>>x;
	while(x<=s){
		n+=1;
		s+=1.0/n;
	}
	cout<<n;
 return 0;
 }

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