#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf(" %d", &n);
  int a = sqrt(n);
  if (a * a == n) {
    printf("%d\n", a * 2);
    return 0;
  } else if ((a + 1) * a >= n) {
    printf("%d\n", a * 2 + 1);
    return 0;
  }
  printf("%d\n", (a + 1) * 2);
}
