import java.util.*;
 
class B {
 
	public void run() {
		Scanner sc = new Scanner(System.in);
		for (String s = sc.nextLine(); !s.equals("."); s = sc.nextLine())
			System.out.println(check(s) ? "yes" : "no");
	}
 
	private boolean check(String s) {
		Stack<Character> st = new Stack<Character>();
		for (char c : s.toCharArray())
			if (c == '(' || c == '[')
				st.push(c);
			else if (c == ')') {
				if (st.isEmpty() || st.pop() != '(')
					return false;
			} else if (c == ']') {
				if (st.isEmpty() || st.pop() != '[')
					return false;
			}
		return st.isEmpty();
	}
 
	public static void main(String[] args) throws Exception {
		new B().run();
	}
}

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

U28gd2hlbiBJIGRpZSAodGhlIFtmaXJzdF0gSSB3aWxsIHNlZSBpbiAoaGVhdmVuKSBpcyBhIHNjb3JlIGxpc3QpLgpbIGZpcnN0IGluIF0gKCBmaXJzdCBvdXQgKS4KSGFsZiBNb29uIHRvbmlnaHQgKEF0IGxlYXN0IGl0IGlzIGJldHRlciB0aGFuIG5vIE1vb24gYXQgYWxsXS4KQSByb3BlIG1heSBmb3JtICkoIGEgdHJhaWwgaW4gYSBtYXplLgpIZWxwKCBJW20gYmVpbmcgaGVsZCBwcmlzb25lciBpbiBhIGZvcnR1bmUgY29va2llIGZhY3RvcnkpXS4KKFsgKChbKCBbIF0gKSAoICkgKCggKSldICkpIF0pLgogLgouCg==

So when I die (the [first] I will see in (heaven) is a score list).
[ first in ] ( first out ).
Half Moon tonight (At least it is better than no Moon at all].
A rope may form )( a trail in a maze.
Help( I[m being held prisoner in a fortune cookie factory)].
([ (([( [ ] ) ( ) (( ))] )) ]).
 .
.