#include <bits/stdc++.h>
using namespace std;
int const N = 2 * 1e5 + 5;
int const md = 1e9 + 7;
int ans = 0;
int i, j, n, m, k, z, y, x, t, mi, ma;
int a[N];
long long dp[N];
char st[N];
int main() {
  scanf("%d", &n);
  t = 1;
  while (t * t < 2 * n - 1) t += 2;
  if (n == 3) t = 5;
  printf("%d", t);
}
