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# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

namespace ABC079
{
    public class QuestionC
    {
        public static void Main(string[] args)
        {
            var abcd = Console.ReadLine().Select(i => (int)i - 48).ToArray();
            var (a, b, c, d) = (abcd[0], abcd[1], abcd[2], abcd[3]);

            var ops = new (bool op1, bool op2, bool op3)[8]
            {
                (false, false, true),
                (false, false, false),
                (false, true, true),
                (false, true, false),
                (true, false, true),
                (true, false, false),
                (true, true, true),
                (true, true, false)
            };

            foreach (var op in ops)
            {
                var result = Calculate(Calculate(Calculate(a, op.op1, b), op.op2, c), op.op3, d);
                if (result == 7)
                {
                    var op1 = op.op1 ? '+' : '-';
                    var op2 = op.op2 ? '+' : '-';
                    var op3 = op.op3 ? '+' : '-';
                    Console.WriteLine($"{a}{op1}{b}{op2}{c}{op3}{d}=7");
                    return;
                }
            }
        }

        private static int Calculate(int left, bool op, int right)
        {
            if (op)
            {
                return left + right;
            }
            else{
                return left - right;
            }
        }
    }
}