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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
import static java.lang.Math.*;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		// 入力
		String s = sc.next();// 

		String[] str = s.split("");

		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);
		int d = Integer.parseInt(str[3]);

		// 計算
		String result;

		result = path("", 1, 0, a, b, c, d);

		// 出力
		System.out.println(result);
	}

	static String path(String p, int depth, int cal, int a, int b, int c, int d){
		if(depth == 1){
			return path(p + a, depth + 1, a, a, b, c, d);
		}
		if(depth == 2){
			return path(p + "+" + b, depth + 1, cal + b, a, b, c, d) + path(p + "-" + b, depth + 1, cal - b, a, b, c, d);
		}
		if(depth == 3){
			return path(p + "+" + c, depth + 1, cal + c, a, b, c, d) + path(p + "-" + c, depth + 1, cal - c, a, b, c, d);
		}
		if(depth == 4){
			return path(p + "+" + d, depth + 1, cal + d, a, b, c, d) + path(p + "-" + d, depth + 1, cal - d, a, b, c, d);
		}

		if(cal == 7) return p + "=7";
		return "";
	}
}