Problem:
Score : 300 points

Problem Statement

Sitting in a station waiting room, Joisino is gazing at her train ticket.

The ticket is numbered with four digits A, B, C and D in this order, each between 0 and 9 (inclusive).

In the formula A op1 B op2 C op3 D = 7, replace each of the symbols op1, op2 and op3 with + or - so that the formula holds.

The given input guarantees that there is a solution. If there are multiple solutions, any of them will be accepted.

Constraints

0≤A,B,C,D≤9

All input values are integers.

It is guaranteed that there is a solution.

Input

Input is given from Standard Input in the following format:

ABCD

Output

Print the formula you made, including the part =7.

Use the signs + and -.

Do not print a space between a digit and a sign.

Sample Input 1

1222

Sample Output 1

1+2+2+2=7

This is the only valid solution.

Sample Input 2

0290

Sample Output 2

0-2+9+0=7

0 - 2 + 9 - 0 = 7 is also a valid solution.

Sample Input 3

3242

Sample Output 3

3+2+4-2=7

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;

namespace Atcoderrr
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            List<Func<int, int,int>> funcList = new List<Func<int, int,int>>();
            funcList.Add(Plus);
            funcList.Add(Minus);
            int[] N = new int[4];
            for (int i = 0; i < 4; i++) N[i] = int.Parse(input[i].ToString());
            List<string> comb = MakeCombination();
            for (int i = 0; i < comb.Count; i++)
            {
                int sum = N[0];
                for (int j = 0; j < 3; j++) sum = (comb[i][j] == '0') ? Plus(sum,N[j+1]):Minus(sum,N[j+1]);
                if(sum == 7)
                {
                    Console.WriteLine(N[0] + s(comb[i][0]) + N[1] +  s(comb[i][1]) + N[2] + s(comb[i][2]) + N[3]+"=7");
                    return;
                }
            }
        }
        static string s(char c)
        {
            return (c == '0') ? "+" : "-";
        }
        static List<string> MakeCombination()
        {
            List<string> ret = new List<string>();
            for (int i = 0; i < 8; i++)
            {
                string str = (Convert.ToString(i, 2)).PadLeft(3,'0');
                ret.Add(str);
            }
            return ret;
        }
        static int Plus(int a , int b)
        {
            return a + b;
        }
        static int Minus(int a, int b)
        {
            return a - b;
        }
    }
}