#include<bits/stdc++.h>
using namespace std;
#define e4 ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define ll  long long
#define test_case int tc;cin>>tc;while(tc--)


int  main() {

	
	  	 e4;

	  	 ll n;

	  	 cin>>n;

	  	 ll val=sqrt(n);

	  	 if(val*(val+1)>n) cout<<(2*val)-1;
	  	 else cout<<(2*val);


	  	
}	
	
		    //          S m o t h e r e d  M a t e !!		 //