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"
)

var n = [4]int{}

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

func dfs(c, v int, s string) string {
	if c == 3 {
		if v == 7 {
			return fmt.Sprintf("%s=7", s)
		}
		return ""
	}
	a := dfs(c+1, v+n[c], fmt.Sprintf("%s+%d", s, n[c]))
	b := dfs(c+1, v-n[c], fmt.Sprintf("%s-%d", s, n[c]))
	if a != "" {
		return a
	}
	return b
}