#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int,int>;
const int N = 1e6+10;
int t,n,m,k,l,r,op,x,y;
int f[N];
bool flag;
char ch;
unordered_map<char,char>mp;
void solve(){
    mp.emplace('>','<');
    mp.emplace(')','(');
    mp.emplace('}','{');
    mp.emplace(']','[');
    stack<char> stk;
    while(cin>>ch){
        if(ch=='<'||ch=='('||ch=='{'||ch=='['){
            stk.push(ch);
        }else{
            if(stk.empty()){
                cout<<"no";
                return ;
            }
            x = stk.top();stk.pop();
            if(mp[ch]!=x){
                cout<<"no";
                return;
            }
        }
    }
    if(!stk.empty()){
        cout<<"no";
        return;
    }
    cout<<"yes";
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);  
    solve();
    return 0;
}