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"
	"os"
	"strconv"
	"bufio"
	"strings"
)

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func check7(sum int, arr []int, eq string) {
	if len(arr) == 0 {
		if sum == 7 {
			fmt.Printf("%s=7\n", eq)
			os.Exit(0)
		}
	} else {
		check7(sum+arr[0], arr[1:], fmt.Sprintf("%s+%d", eq, arr[0]))
		check7(sum-arr[0], arr[1:], fmt.Sprintf("%s-%d", eq, arr[0]))
	}
}

func main(){
	var abcd string
	fmt.Scan(&abcd)
	arr := make([]int, 4)
	for i, v := range abcd {
		arr[i] = int(v - '0')
	}
	check7(arr[0], arr[1:], strconv.Itoa(arr[0]))
}