Problem:
Score : 100 points

Problem Statement

You are given two positive integers a and b.
Let x be the average of a and b.
Print x rounded up to the nearest integer.

Constraints

a and b are integers.

1 \leq a, b \leq 100

Input

Input is given from Standard Input in the following format:

a b

Output

Print x rounded up to the nearest integer.

Sample Input 1

1 3

Sample Output 1

2

The average of 1 and 3 is 2.0, and it will be rounded up to the nearest integer, 2.

Sample Input 2

7 4

Sample Output 2

6

The average of 7 and 4 is 5.5, and it will be rounded up to the nearest integer, 6.

Sample Input 3

5 5

Sample Output 3

5

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
#include <cstdlib>

// lib/detail/ceil_and_floor.hpp
#ifndef DETAIL_CEIL_AND_FLOOR_HPP
#define DETAIL_CEIL_AND_FLOOR_HPP

namespace tools {
  template <typename T>
  constexpr T floor(T lhs, T rhs);

  template <typename T>
  constexpr T ceil(T lhs, T rhs);

  template <typename T>
  constexpr T floor(const T lhs, const T rhs) {
    return
      lhs >= 0 && rhs >= 0 ?
        lhs / rhs :
      lhs < 0 && rhs >= 0 ?
        -ceil<T>(-lhs, rhs) :
      lhs >= 0 && rhs < 0 ?
        -ceil<T>(lhs, -rhs) :
        floor<T>(-lhs, -rhs);
  }

  template <typename T>
  constexpr T ceil(const T lhs, const T rhs) {
    return
      lhs >= 0 && rhs >= 0 ?
        (lhs - 1 + rhs) / rhs :
      lhs < 0 && rhs >= 0 ?
        -floor<T>(-lhs, rhs) :
      lhs >= 0 && rhs < 0 ?
        -floor<T>(lhs, -rhs) :
        ceil<T>(-lhs, -rhs);
  }
}

#endif

// lib/quo.hpp
#ifndef QUO_H
#define QUO_H

/*
a == tools:quo(a, b) * b + tools::mod(a, b)
0 <= tools::mod(a, b) < std::abs(b)
*/

namespace tools {
  template <typename T>
  constexpr T quo(const T lhs, const T rhs) {
    return lhs > 0 ? lhs / rhs : rhs > 0 ? -((-lhs - 1 + rhs) / rhs) : (-lhs - 1 + -rhs) / -rhs;
  }
}

#endif

// lib/floor.hpp
#ifndef FLOOR_HPP
#define FLOOR_HPP


/*
usage:

tools::floor(5, 3) // => 1 (i.e., floor(5 / 3))
*/

#endif

// lib/ceil.hpp
#ifndef CEIL_HPP
#define CEIL_HPP


/*
usage:

tools::ceil(5, 3) // => 2 (i.e., ceil(5 / 3))
*/

#endif

// lib/mod.hpp
#ifndef MOD_HPP
#define MOD_HPP


/*
a == tools:quo(a, b) * b + tools::mod(a, b)
0 <= tools::mod(a, b) < std::abs(b)
*/

namespace tools {
  template <typename T>
  constexpr T mod(const T lhs, const T rhs) {
    return lhs - quo(lhs, rhs) * rhs;
  }
}

#endif

// lib/round.hpp
#ifndef ROUND_HPP
#define ROUND_HPP


/*
usage:

tools::round(5, 3) => 2
*/

namespace tools {
  template <typename T>
  constexpr T round(const T lhs, const T rhs) {
    return std::abs(rhs) % 2 == 0
      ? mod(lhs, rhs) == std::abs(rhs) / 2
        ? floor(lhs, rhs) % 2 == 0
          ? floor(lhs, rhs)
          : ceil(lhs, rhs)
        : mod(lhs, rhs) < std::abs(rhs) / 2
          ? floor(lhs, rhs)
          : ceil(lhs, rhs)
      : mod(lhs, rhs) <= std::abs(rhs) / 2
        ? floor(lhs, rhs)
        : ceil(lhs, rhs);
  }
}

#endif

// main.cpp

int main() {
  std::int_fast64_t a, b;
  std::cin >> a >> b;
  std::cout << tools::round<std::int_fast64_t>(a + b, 2) << std::endl;
  return 0;
}