#include <bits/stdc++.h> using namespace std; int main() { char a[3000]; int flag = 0; fgets(a,3000,stdin); int i = 0; int maxlen = 0; string str1 = "",maxstr = ""; int len = 0; while(a[i] != '.') { if(a[i] != ' ') { len++; str1 += a[i]; if(a[i] == 'a') { flag = 1; } } else { if(flag && len > maxlen) { maxstr = str1; maxlen = len; flag = 0; } str1 = ""; len = 0; } i++; } if(maxstr == "") { cout<<"NO"<<endl; } else { cout<<maxstr<<endl; } return 0; }