#include<bits/stdc++.h>
using namespace std;

#define  ll  long long

int main(){
    int tc = 1;
    //cin >> tc;
    while(tc--){
        int n;
        cin >> n;
        ll sq = sqrt(n);
        ll cn = sq - 1;
        cn *= 2;
        if(sq * sq <= n) cn++;
        if(sq * (sq + 1) <= n) cn++;
        cout << cn << endl;
    }
}