Problem Description

Given three integers \(a, b, c\), it is guaranteed that \(b \neq 0\).

• If \(a + b = c\), please output \(\texttt{plus}\).
• If \(a - b = c\), please output \(\texttt{minus}\).
• If neither of the above conditions is met, output \(\texttt{illegal}\).

Input Format

The input consists of a single line with three integers, representing \(a, b, c\) in order.

Output Format

Output a single string representing the answer.

Sample Input and Output

Sample Input #1

1 2 3

Sample Output #1

plus

Sample Input #2

3 2 1

Sample Output #2

minus

Sample Input #3

1 1 4

Sample Output #3

illegal

Notes

Data Range and Constraints

For all test cases, it is guaranteed that \(-2^{31} \leq a, b, c < 2^{31}\) and \(b \neq 0\).

见题面 Input 部分

见题面 Output 部分