POJ 1126

#include <stdio.h>
#include <string>
#include <iostream>

using namespace std;

int main()
{
  //  freopen("acm.acm","r",stdin);
  //  freopen("out.acm","w",stdout);
    
    string s;
    int len;
    int i;
    int index;
    while(cin>>s)
    {
        index = 0;
        len = s.length();
        for(i = len - 1; i >= 0; -- i)
        {
            if(s[i] >= ‘p‘ && s[i] <= ‘z‘)
            {
                ++ index; 
            }
            else if(s[i] == ‘C‘ || s[i] == ‘D‘ || s[i] == ‘E‘ || s[i] == ‘I‘)
            {
                if(index >= 2)
                {
                    -- index;
                }
                else 
                {
                    index = 0;
                    break;
                }
            }
            else if(s[i] == ‘N‘)
            {
                if(index == 0)
                {
                    break;
                }
            }
            else
            {
                index = 0;
                break;
            }
        }
        if(index == 1)
        {
            cout<<"YES"<<endl;
        }
        else
        {
            cout<<"NO"<<endl;
        }
    }
    return 0;
}