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++ (Clang 10.0.0) (judge verdict: Accepted)

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <bitset>
typedef long long ll;
#define rep(i,n) for(int i = 0;i<n;++i)
#define repnc(bit,k,n) for (int bit = (1<<k)-1;bit < (1<<n); bit = next_combination(bit))
#define repi(itr,vec) for(auto itr = vec.begin();itr!=vec.end();++itr)
using namespace std;

/* next combination */
int next_combination(int sub) {
  int x = sub & -sub, y = sub + x;
  return (((sub & ~y) / x) >> 1) | y;
}

int int_substr(string abcd, int n){
  return abcd[n]-'0';
}

int main(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
  string abcd;
  cin >> abcd;
  string ans;
  ans = abcd[0];
  rep(bit, 1<<3){
    int calc = int_substr(abcd,0);
    char opt[3];
    rep(i, 3){
      if(bit&1<<i){
        opt[i] = '+';
        calc+=int_substr(abcd,i+1);
      }else{
        opt[i] = '-';
        calc-=int_substr(abcd,i+1);
      }
    }
    if(calc == 7){
      rep(i, 3){
        ans+=opt[i];ans+=abcd[i+1];
      }
      break;
    }
  }
  cout << ans << "=7\n";
        return 0;
}