#include <bits/stdc++.h>
using namespace std;
string s;
int main(){
    while(true){
        getline(cin, s);
        if(s == ".") break;
        stack<char> stk;
        bool isImp = false;
        for(int i = 0; i < s.size(); i++){
            if(s[i] == '(' || s[i] == '[') stk.push(s[i]);
            else if(stk.size() && s[i] == ')'){
                if(stk.top() == '(') stk.pop();
                else isImp = true;
            } else if(stk.size() && s[i] == ']'){
                if(stk.top() == '[') stk.pop();
                else isImp = true;
            }
        }
        if(stk.size()) isImp = true;
 
        if(isImp) cout << "no\n";
        else cout << "yes\n";
    }
}

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

U28gd2hlbiBJIGRpZSAodGhlIFtmaXJzdF0gSSB3aWxsIHNlZSBpbiAoaGVhdmVuKSBpcyBhIHNjb3JlIGxpc3QpLgpbIGZpcnN0IGluIF0gKCBmaXJzdCBvdXQgKS4KSGFsZiBNb29uIHRvbmlnaHQgKEF0IGxlYXN0IGl0IGlzIGJldHRlciB0aGFuIG5vIE1vb24gYXQgYWxsXS4KQSByb3BlIG1heSBmb3JtICkoIGEgdHJhaWwgaW4gYSBtYXplLgpIZWxwKCBJW20gYmVpbmcgaGVsZCBwcmlzb25lciBpbiBhIGZvcnR1bmUgY29va2llIGZhY3RvcnkpXS4KKFsgKChbKCBbIF0gKSAoICkgKCggKSldICkpIF0pLgooLgou

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)].
([ (([( [ ] ) ( ) (( ))] )) ]).
(.
.