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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>

int sum(int a,int b);
int sub(int a,int b);

int main(void){
	int i,n,a,b,c,d,x,op1,op2,op3,cnt=0;
	char op[2]={'+','-'};
	scanf("%d",&n);
	a=(n/1000)%10;
	b=(n/100)%10;
	c=(n/10)%10;
	d=n%10;
	for(;;){
		x=0;
		op1=0;
		op2=0;
		op3=0;
		for(i=0;i<3;i++){
			if((cnt<3)||(cnt==4)){
				x=sum(a,b);
				if(cnt<2){
					x=sum(x,c);
					if(cnt==0){
						x=sum(x,d);
					}else{
						x=sub(x,d);
						op3=1;
					}
				}else{
					x=sub(x,c);
					op2=1;
					if(cnt==2){
						x=sum(x,d);
					}else{
						x=sub(x,d);
						op3=1;
					}
				}
			}else{
				x=sub(a,b);
				op1=1;
				if((cnt==3)||(cnt==6)){
					x=sum(x,c);
					if(cnt==3){
						x=sum(x,d);
					}else{
						x=sub(x,d);
						op3=1;
					}
				}else{
					x=sub(x,c);
					op2=1;
					if(cnt==5){
						x=sum(x,d);
					}else{
						x=sub(x,d);
						op3=1;
					}
				}
			}
		}
		if(x==7){
			break;
		}
		cnt++;
	}
	printf("%d%c%d%c%d%c%d=7",a,op[op1],b,op[op2],c,op[op3],d);
	return 0;
}

int sum(int a,int b){
	return a+b;
}

int sub(int a,int b){
	return a-b;
}