tijie<AC>

#include<bits/stdc++.h>
using namespace std;
int main(){
	char t = ' ';
    string s;
    cin >> s;
    for (int i = 0; i < s.size(); i++) {
    	if (t ==' ' && s[i] == 'a')
        	t = 'a';
        if (t =='a' && s[i] == 'c')
        	t = 'c';
        if (t =='c' && s[i] == 'g')
        	t = 'g';
        if (t =='g' && s[i] == 'o')
        	t = 'o';
    }
    if (t == 'o') cout << "YES";
    else cout << "NO";
    return 0;
}