#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#define ll long long
using namespace std;

int main() {
    ll N;
    cin>>N;
    long double x=sqrt(N);
    ll A=x;
    if(A*A>N){
        A--;
    }
    cout<<A+N/(A+1)<<endl;
}