Expression Parenthesis Matching (Stack)

Problem Background

Special for beginners, ^_^

Problem Description

Suppose an expression consists of English letters (lowercase), operators (+, -, *, /), and left/right parentheses, with @ as the terminator of the expression. Please write a program to check whether the left and right parentheses in the expression match. If they match, return YES; otherwise return NO. The expression length is less than $255$, and there are fewer than $20$ left parentheses.

Input Format

One line of data: the expression.

Output Format

One line: YES or NO. These words must be printed exactly as shown (do not translate).

Sample Input 1

2*(x+y)/(1-x)@

Sample Output 1

YES

Sample Input 2

(25+x)*(a*(a+b+b)@

Sample Output 2

NO

Constraints

Time limit 1s, memory limit 1024KiB for each test case.