uva 10391 Compound Words

#include<bits/stdc++.h>

using namespace std;

int main()
{
    string s,c;
    vector<string>v1;
   map<string,int>mp;
      while(cin>>s){
           v1.push_back(s);
        mp[s]++;

    }
    for(long int i=0;i<v1.size();i++)
    {
         for(long int j=0;j<v1.size();j++)
          {
            c= v1[i]+v1[j];
          if(mp[c]!=0) {
            cout<<c<<endl;
          mp[c]=0;
          }
          }

    }

}