#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
 
int main(void)
{
	while (1)
	{
		string arr;	//원본
		string brr;	//괄호만
		getline(cin, arr, '.');	//'.'이 입력되는 순간까지만 입력
		bool flag = true;		//true라면 yes, false라면 no
		if (arr.empty()) break;	//아무것도 없다면 종료
 
		for (int i = 0; i < arr.length(); i++)
		{
			if (arr[i] == '(' || arr[i] == '[')		//열린 괄호는 전부 push
				brr.push_back(arr[i]);
			else if (arr[i] == ']')
			{
				if (brr.empty() || brr[brr.length() - 1] != '[')	//비어있거나 열린 대괄호가 아니라면 비교 중지
				{
					flag = false;
					break;
				}
				else brr.pop_back();
			}
			else if (arr[i] == ')')
			{
				if (brr.empty() || brr[brr.length() - 1] != '(')	//비어있거나 열린 소괄호가 아니라면 비교 중지
				{
					flag = false;
					break;
				}
				else brr.pop_back();
			}
		}
		if (flag && brr.empty()) cout << "yes" << endl;		//brr에 괄호가 없고 중간에 정지되지 않았다면 yes
		else cout << "no" << endl;
		cin.ignore();		//입력 버퍼 비워주기
	}
}

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

U28gd2hlbiBJIGRpZSAodGhlIFtmaXJzdF0gSSB3aWxsIHNlZSBpbiAoaGVhdmVuKSBpcyBhIHNjb3JlIGxpc3QpLgpbIGZpcnN0IGluIF0gKCBmaXJzdCBvdXQgKS4KSGFsZiBNb29uIHRvbmlnaHQgKEF0IGxlYXN0IGl0IGlzIGJldHRlciB0aGFuIG5vIE1vb24gYXQgYWxsXS4KQSByb3BlIG1heSBmb3JtICkoIGEgdHJhaWwgaW4gYSBtYXplLgpIZWxwKCBJW20gYmVpbmcgaGVsZCBwcmlzb25lciBpbiBhIGZvcnR1bmUgY29va2llIGZhY3RvcnkpXS4KKFsgKChbKCBbIF0gKSAoICkgKCggKSldICkpIF0pLgogLgou

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