Dundee The Crocodile

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <map>

using namespace std;


int main() {
    map<string, int> words;
    string word;
    while(cin >> word){
        words[word]++;
    }
    for(auto wordPair : words){
        if(wordPair.second == 1)
            cout << wordPair.first << endl;
    }
}