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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
void func(int,int);
int n[4],s[3],s2[3];
int main(void)
{
	int i;
	char a[5],ss[3]="-+";
	scanf("%s",a);
	for(i=3;i>=0;i--) n[i]=a[i]-'0';
	//for(i=0;i<4;i++) printf("%d\n",n[i]);
	func(0,n[0]);
	for(i=0;i<3;i++){
		printf("%d%c",n[i],ss[s2[i]]);
	}
	printf("%d=7\n",n[3]);
	return 0;
}
void func(int nn,int sum)
{
	int i;
	if(nn==3){
		if(sum==7){
			for(i=0;i<3;i++) s2[i]=s[i];
		}	
	}
	else{
		s[nn]=0;
		func(nn+1,sum-n[nn+1]);
		s[nn]=1;
		func(nn+1,sum+n[nn+1]);
	}
}