#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, n, tmp;
  scanf("%d", &x);
  if (x == 3) {
    printf("5\n");
    return 0;
  }
  n = 1;
  tmp = 1;
  while (tmp < x) {
    n += 2;
    tmp = (n * n + 1) / 2;
  }
  printf("%d\n", n);
}
