Codeforce - Registration system

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin>>n;
    cin.ignore();
    map<string,int>mp;
    string s;
    while(n--)
    {
        getline(cin,s);
        if(mp[s]==0)
        {
            printf("OK\n");
            mp[s]++;
        }
        else
        {
            cout<<s<<mp[s]<<endl;
            mp[s]++;
        }
        s.clear();
    }
    return 0;
}