C language

Read in n, then n lastnames, and check to see if the first in the list is ever repeated again.

Sample Run #1

Enter n, followed by n Last names (each last name must be a single word): 5 Reagan Bush Clinton Bush Obama First name in list is not repeated.

Sample Run #2

Enter n, followed by n Last names (each last name must be a single word): 4 Bush Clinton Bush Obama First name in list is repeated.

Note: I must use this line like this: if(strcmp(first, last)<0) somehow.