#include <iostream>
#include <sstream>
#include <string.h>
#include <algorithm>

using namespace std;

int main() {
    string search("problem");
    string line;
    int lineNumber = 0;

    //cout << "enter a sentence :\n>" << search << endl;
    while (getline(cin, line, '\n')) {
        lineNumber++;
        transform(line.begin(), line.end(), line.begin(), ::tolower);
        if (lineNumber > 1000){
            break;
        }
        if(line.length() >80){
            break;
        }


        if (line.find(search) != std::string::npos) {
            cout << "yes" << endl;
        }else {
            cout << "no" << endl;
        }

    }
    return 0;

}