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: Wrong Answer)

package main

import (
	"fmt"
	"strconv"
)

var n = [4]int{}

func main() {
	fmt.Scanf("%1d%1d%1d%1d", &n[0], &n[1], &n[2], &n[3])
	r := dfs(0, 0, "")
	fmt.Println(r + "=7")
}

func dfs(c, v int, s string) string {
	if c == 4 {
		if v == 7 {
			return s[1:]
		}
		return ""
	}

	r := ""
	for i := c; i < 4; i++ {
		r = dfs(c+1, v+n[i], s+"+"+strconv.Itoa(n[i]))
		if len(r) > 0 {
			return r
		}
		r = dfs(c+1, v-n[i], s+"-"+strconv.Itoa(n[i]))
		if len(r) > 0 {
			return r
		}
	}

	return r
}