#include <bits/stdc++.h>
using namespace std;
long long n, k, ans = 0, i = 0, j = 0;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) {
    int n;
    cin >> n;
    if (n == 1) {
      cout << 2;
      exit(0);
    }
    int x = sqrt(n);
    n = n - x * x;
    if (!n) {
      cout << 2 * x;
      exit(0);
    }
    if (n - x > 0)
      cout << 2 * x + 2;
    else
      cout << 2 * x + 1;
  }
}
