#include <bits/stdc++.h>
using namespace std;
int n;
int main() {
  scanf("%d", &n);
  int x = sqrt(n);
  if (x * x == n)
    printf("%d\n", 2 * x);
  else {
    int r = n / x;
    int p = x + r;
    if (n % x != 0) p++;
    printf("%d\n", p);
  }
}
