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 Java (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.*;
import java.math.*;
import java.util.*;
public class Main { 
 
	public static void main(String[] args) { 
		FastScanner I = new FastScanner(); //Input
		OutPut O = new OutPut(); //Output
		ArrayList<Character> ticket = new ArrayList<Character>();
		String S = I.next();
		for (int i = 0; i<4; i++) ticket.add(S.charAt(i));
		for (int mask = 0; mask < (1<<3); mask++){ //1<<x creates x empty slots through 
		//a binary string representation
			char[] seq = new char[3]; //Sequence if +/-
			for (int chk = 0; chk < 3; chk++) {
				if ((mask>>chk)%2==1) seq[3-chk-1]='+';
				else seq[3-chk-1]='-';
			}
			int cur = S.charAt(0)-'0';
			for (int chk = 0; chk<3; chk++) {
				int next = S.charAt(chk+1)-'0'; //Next digit of ticket
				if (seq[chk]=='+') cur+=next;
				else cur-=next;
			}
			if (cur==7) {
				StringBuilder ans = new StringBuilder();
				ans.append(S.charAt(0));
				for (int i = 0; i < 3; i++) {
					ans.append(seq[i]);
					ans.append(S.charAt(i+1));
				}
				String end = "=7";
				ans.append(end);
				O.pln(ans);
				break;
			}
		}
	}
	public static ArrayList<String> perms(int N,int limit){
		if (N==1) {
			ArrayList<String> ret = new ArrayList<String>();
			for (int i = 0; i < limit; i++) {
				 ret.add(Integer.toString(i));
			}
			return ret;
		}
		ArrayList<String> prev = perms(N-1,limit);
		ArrayList<String> ret = new ArrayList<String>();
		for (int i = 0; i < prev.size(); i++) {
			String cur = prev.get(i);
			boolean[] vis = new boolean[10];
			for (int j = 0; j < cur.length(); j++) {
				int dig = Integer.parseInt(cur.substring(j,j+1));
				vis[dig]=true;
			}
			if (!vis[1]) {
				for (int next = 0; next < limit; next++) {
					if (!vis[next]) {
						String add = cur;
						add+=Integer.toString(next);
						ret.add(add);
					}
				}
			}else ret.add(cur); //Just use previous end on 1 sequence	
		}
		return ret;
	}
	public static long ceil(long num, long den) {long ans = num/den; if (num%den!=0) 
	ans++; return ans;}
	public static long GCD(long a, long b) {
		if (a==0||b==0) return Math.max(a,b);
		return GCD(Math.min(a, b),Math.max(a, b)%Math.min(a, b));
	}
	public static long FastExp(long base, long exp, long mod) {
		long ans=1;
		while (exp>0) {
			if (exp%2==1) ans*=base;
			exp/=2;
			base*=base;
			base%=mod;
			ans%=mod;
		}
		return ans;
	}
	public static long ModInv(long num,long mod) {return FastExp(num,mod-2,mod);}
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		int nextInt() {return Integer.parseInt(next());}
		long nextLong() {return Long.parseLong(next());};
	}
	static class OutPut{
		PrintWriter w = new PrintWriter(System.out);
		void pln(double x) {w.println(x);w.flush();}
		void pln(int x) {w.println(x);w.flush();}
		void pln(long x) {w.println(x);w.flush();}
		void pln(String x) {w.println(x);w.flush();}
		void pln(char x) {w.println(x);w.flush();}
		void pln(StringBuilder x) {w.println(x);w.flush();}
		void p(int x) {w.print(x);w.flush();}
		void p(long x) {w.print(x);w.flush();}
		void p(String x) {w.print(x);w.flush();}
		void p(char x) {w.print(x);w.flush();}
		void p(StringBuilder x) {w.print(x);w.flush();}
	}
}