# Valid Expression CodeChef Solution

### We Are Discuss About CODECHEF SOLUTION

Valid Expression CodeChef Solution

## Problem

The correct way of evaluating an expression with ∗,+, and  is, first multiplication, then addition, and then subtraction. For example, the expression 2+3∗7−5=2+21−5=23−5=18.

You are given integers  and . Your task is to generate a string  of length  consisting only of ∗,+, and  such that when these  operators are placed in order between (�+1) ones, the result of the expression becomes .
For example, if �= ++-*-, the resulting expression is 1+1+1−1∗1−1, which is then evaluated based on the rules above.

If multiple such strings exist, print any of them. If no such string exists, print −1 instead.

### Input Format

• The first line of input will contain a single integer , denoting the number of test cases.
• Each test case consists of two space-separated integers  and  — the number of characters in the string and the result of expression after appending (�+1) ones between all operators.

### Output Format

For each test case, output on a new line a string  of length  consisting only of ∗,+, and  that satisfies the given condition.

If multiple such strings exist, print any of them. If no such string exists, print −1 instead.

### Constraints

• 1≤�≤2000
• 1≤�≤105
• −105≤�≤105
• The sum of  over all test cases won’t exceed 2⋅105.

### Sample 1:

Input

Output

3
3 4
2 -5
3 1

+++
-1
*+-


### Explanation:

Test case 1: A possible string satisfying the condition is +++. The corresponding expression is 1+1+1+1=4 which is equal to .

Test case 2: It can be proven that no such string with length �=2 exists such that the corresponding expression evaluates to −5.

Test case 3: A possible string satisfying the condition is *+-. The corresponding expression is 1∗1+1−1=1+1−1=2−1=1 which is equal to .
Note that there are other valid strings, such as +*- and -*+. Any valid string will be accepted as output.

## SOLUTION

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