Alex and broken contest CodeForces - 877A

/*
    Name:
    Copyright:
    Author:
    Date: 2018/5/2 10:45:16
    Description:
    要求出现一个朋友的名字，仅一次
*/
#include <iostream>
#include <cstdio>
#include <string>
using namespace std;
int main()
{
//    freopen("in.txt", "r", stdin);
    string fname1 = "Danil";
    string fname2 = "Olya";
    string fname3 = "Slava";
    string fname4 = "Nikita";
    string fname5 = "Ann";
    string str;
    while (cin>>str) {
        int flag = ;
        if (str.find(fname1) != -) {
            int pos = ;
            string tmp = str;
            while ((pos = tmp.find(fname1)) != -) {
                flag ++;
                tmp = tmp.substr(pos + );
                if (flag >= ) break;
            }
        }
        if (str.find(fname2) != -) {
            int pos = ;
            string tmp = str;
            while ((pos = tmp.find(fname2)) != -) {
                flag ++;
                tmp = tmp.substr(pos + );
                if (flag >= ) break;
            }
        }
        if (str.find(fname3) != -) {
            int pos = ;
            string tmp = str;
            while ((pos = tmp.find(fname3)) != -) {
                flag ++;
                tmp = tmp.substr(pos + );
                if (flag >= ) break;
            }
        }
        if (str.find(fname4) != -) {
            int pos = ;
            string tmp = str;
            while ((pos = tmp.find(fname4)) != -) {
                flag ++;
                tmp = tmp.substr(pos + );
                if (flag >= ) break;
            }
        }
        if (str.find(fname5) != -) {
            int pos = ;
            string tmp = str;
            while ((pos = tmp.find(fname5)) != -) {
                flag ++;
                tmp = tmp.substr(pos + );
                if (flag >= ) break;
            }
        }
        if (flag == ) {
            cout<<"YES"<<endl;
        } else {
            cout<<"NO"<<endl;
        }
    }
    return ;
}