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"
)

const n = 7

var (
	b2i = map[bool]int{false: 0, true: 1}
	seq = []int{}
	flg bool
)

func dfs(left, i int, ops []bool) {
	if i == len(seq) {
		if left == 0 && !flg {
			for i := range seq {
				if i != 0 {
					fmt.Print([...]string{"-", "+"}[b2i[ops[i]]])
				}
				fmt.Print(seq[i])
			}
			fmt.Printf("=%d\n", n)
			flg = true
		}
		return
	}
	dfs(left-seq[i], i+1, append(ops, true))
	if i != 0 {
		dfs(left+seq[i], i+1, append(ops, false))
	}
}

func main() {
	var abcd string
	fmt.Scan(&abcd)

	for _, c := range abcd {
		seq = append(seq, int(c)-'0')
	}
	dfs(n, 0, []bool{})
}