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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
#include <algorithm>
#define rep(i,n) for(int i=0;i<(n);++i)
using namespace std;
typedef long long ll;

int a[4];
char s[5];
bool dfs(int i,int sum) {
    if(i==4) {
        if(sum==7) {
            return true;
        }
        else    return false;
    }
    if(dfs(i+1,sum+a[i])) {
          s[i]='+';  return  true;
    }
    if(dfs(i+1,sum-a[i])) {
       s[i]='-';  return true;
    }
    return false;
}

int main() {
    rep(i,4)    cin>>a[i];
    if(dfs(1,a[0])==true) {
        printf("%d%c%d%c%d%c%d",a[0],s[1],a[1],s[2],a[2],s[3],a[3]);
    }
  return 0;
}