// How do I input a map
// Read a map from the standard input stream
cout << "Enter a map from " << domain << " into " << range << endl
<< "For example if domain={a,b,c} and range={x,y,z} : { a -> x y , b -> y z , c -> x z }" << endl;
cin >> m;
cout << "You entered : " << m << endl;