#include <bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
long long i, j, k, l, n, m, p, q, r, d, su, sx, sy,
    prod = 1, maxi, a, b, c, w, x, y, o, e, f, mini = 100000000000000, t, cnt;
string s, s1, s2;
long long ar[300005], dp[300005], br[300005];
vector<long long> adj[300005];
long long modularExponentiation(long long x, long long n) {
  if (n == 0)
    return 1;
  else if (n % 2 == 0)
    return modularExponentiation((x * x) % 998244353, n / 2);
  else
    return (x * modularExponentiation((x * x) % 998244353, (n - 1) / 2)) %
           998244353;
}
bool sortbysec(const pair<long long, long long> &a,
               const pair<long long, long long> &b) {
  return (a.second < b.second);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int ti = 1;
  while (ti--) {
    cin >> n;
    m = sqrt(n);
    if (m * m == n) {
      cout << 2 * m;
    } else if (m * (m + 1) >= n)
      cout << 2 * m + 1;
    else
      cout << 2 * m + 2;
  }
  return 0;
}
