#include<bits/stdc++.h>
using namespace std;
string s;
stack<char>st;
int main(){
	cin>>s;
	for(int i=0;i<s.size();i++){
		if(s[i]==')'){
			if(st.empty()||st.top()!='('){
				cout<<"no";
				return 0;
			}
		}
		else if(s[i]==']'){
			if(st.empty()||st.top()!='['){
				cout<<"no";
				return 0;
			}
		}
		else if(s[i]=='}'){
			if(st.empty()||st.top()!='{'){
				cout<<"no";
				return 0;
			}
		}
		st.push(s[i]);
	}
	if(st.!empty())cout<<"no";
	else cout<<"yes";
	return 0;
}
/**************************************************************
	Problem: 1486
	User: chenshuo
	Language: C++
	Result: Compile Error
****************************************************************/