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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"fmt"
	"strconv"
)

var s string
var ans []byte

func dfs(i, sum int) bool {
	if i == 4 {
		if sum == 7 {
			return true
		}
		return false
	}
	a, _ := strconv.Atoi(string(s[i]))
	if dfs(i+1, sum+a) {
		ans = append([]byte{'0' + byte(a)}, ans...)
		ans = append([]byte{'+'}, ans...)
		return true
	}
	if dfs(i+1, sum-a) {
		ans = append([]byte{'0' + byte(a)}, ans...)
		ans = append([]byte{'-'}, ans...)
		return true
	}
	return false
}

func main() {
	fmt.Scan(&s)
	ans = make([]byte, 0)
	a, _ := strconv.Atoi(string(s[0]))
	dfs(1, a)
	ans = append([]byte{'0' + byte(a)}, ans...)
	fmt.Println(string(ans) + "=7")
}