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>
using namespace std;

//int ans;
vector<int> num(4);
vector<char> ansv(3);

void dfs2(int x, char ch, vector<char> fct, int ans){
	if(x == 4){
      	if(ans == 7){
        	for(int i = 0; i < 3; i++){ansv.at(i) = fct.at(i);}}
    	return;}
  	
  	if(ch == '+'){
      	fct.push_back('+');
    	ans += num.at(x);
      	dfs2(x+1,'+',fct,ans);
      	dfs2(x+1,'-',fct,ans);
    	}
	if(ch == '-'){
      	fct.push_back('-');
    	ans -= num.at(x);
      	dfs2(x+1,'+',fct,ans);
      	dfs2(x+1,'-',fct,ans);
    	}
  
  	return;
}

void dfs(int x){
  	int ans = num.at(x);
	dfs2(x+1, '+', vector<char>(0),ans);
  	dfs2(x+1, '-',vector<char>(0),ans);
  	return;
}

int main(){
	vector<char> s(4);	for(int i = 0; i < 4; i++){
    	cin >> s.at(i);
    	num.at(i) = s.at(i) - '0';}
		dfs(0);
  	
  	for(int i = 0; i < 3; i++){
    	cout << ansv.at(i) << " ";}
}