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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)


import java.util.*;
import java.util.stream.Collectors;



public class Main {
    public static int[] ints;
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        String[] strings=scanner.next().split("");
        ints=new int[strings.length];
        for(int i=0;i<ints.length;i++){
            ints[i]=Integer.parseInt(strings[i]);
        }
        char[] chars=new char[ints.length-1];
        func(3,chars,7);

    }
    public static void func(int index,char[] chars,int val){
        //System.out.println("call func!");
        //System.out.println(String.format("\tindex=%d,chars=[%c,%c,%c],val=%d",index,chars[0],chars[1],chars[2],val));
        if(index==0){
            if(val==ints[0]){
                for(int i=0;i<ints.length-1;i++){
                    System.out.print(String.format("%d%c",ints[i],chars[i]));
                }
                System.out.println(String.format("%d=7",ints[ints.length-1]));
                System.exit(0);
            }else{
                return;
            }
        }
        char[] chars1=Arrays.copyOf(chars,chars.length);
        char[] chars2=Arrays.copyOf(chars,chars.length);
        chars1[index-1]='+';
        chars2[index-1]='-';
        func(index-1,chars1,val-ints[index]);
        func(index-1,chars2,val+ints[index]);


    }
}