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 (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>

int             g_flag = 0;

void    print_answer(char *nums, char *option)
{
        int             i;
        char    answer[9];

        for (i = 0; i < 3; i++)
        {
                answer[i * 2] = nums[i];
                answer[i * 2 + 1] = option[i];
        }
        answer[6] = nums[3];
        answer[7] = '=';
        answer[8] = '7';
        answer[9] = '\0';
        printf("%s\n", answer);
}

int             check_seven(char *nums, char *option)
{
        int i;
        int sum;

        sum = nums[0] - '0';
        for (i = 0; i < 3; i++)
        {
                if (option[i] == '+')
                        sum += nums[i + 1] - '0';
                else
                        sum -= nums[i + 1] - '0';
        }
        if (sum == 7)
                return (1);
        else
                return (0);
}

void    culc_seven(char *nums, char *option, int i)
{
        if (g_flag == 1)
                return ;
        if (i == 3)
        {
                if (check_seven(nums, option))
                {
                        print_answer(nums, option);
                        g_flag = 1;
                }
                return ;
        }
        option[i] = '+';
        culc_seven(nums, option, i + 1);
        option[i] = '-';
        culc_seven(nums, option, i + 1);
}

int             main(void)
{
        char nums[5];
        char option[4] = "0000";

        scanf("%s", nums);
        culc_seven(nums, option, 0);
        return (0);
}