#line 1 "sqrt.test.cpp"
#define PROBLEM "https://yukicoder.me/problems/no/1162"

#line 1 "/workspaces/Aice/Src/Integer/Util.hpp"



#line 1 "/workspaces/Aice/Src/Primitive/TypeDef.h"



#include <cstdint>

using s32 = int_fast32_t;
using s64 = int_fast64_t;

using u32 = uint_fast32_t;
using u64 = uint_fast64_t;

using f32 = float;
using f64 = double;
using f128 = long double;


#line 5 "/workspaces/Aice/Src/Integer/Util.hpp"

#include <cmath>
#include <cassert>

namespace aice {
namespace integer {

class Util {
public:

  /**
   * sqrt(target)以下の最大の整数を計算します
   * @param target 平方数を計算したい値。0以上である必要があります
   */
  template<class T>
  static T sqrt_floor(T target) {
    assert(target >= 0);
    T cand = std::sqrt(target);
    while (cand * cand > target) cand--;
    while ((cand + 1) * (cand + 1) <= target) cand++;
    return cand;
  }
};

}
}

#line 4 "sqrt.test.cpp"

#include <iostream>

int main() {
  s64 X;
  std::cin >> X;

  s64 sqrt_X = aice::integer::Util::sqrt_floor(X);

  s64 ans = sqrt_X * 2LL;
  if (X / sqrt_X == sqrt_X) ans--;

  std::cout << ans << std::endl;
}