https://codeforces.com/problemset/problem/4/C
#includeusing namespace std; unordered_map mp; int main(void) { int n; cin>>n; for(int i=0;i >s; if(mp.count(s)==0) cout<<"OK"<

https://codeforces.com/problemset/problem/4/C
#includeusing namespace std; unordered_map mp; int main(void) { int n; cin>>n; for(int i=0;i >s; if(mp.count(s)==0) cout<<"OK"<