#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int main() {
    long long n;
    cin >> n;
    long long m = 0;
    for (long long i = floor(sqrt(n)); i <= n; i++) {
        if (m == n / i) {
            cout << i + n / i - 2 << endl;
            return 0;
        }
        m = n / i;
    }
    cout << n << endl;
}