program ABC_075_A_OneoutofThree
   implicit none
   integer A, B, C
   read(*, *) A, B, C
   if(A == B) then
       write(*, *) C
   else if(A == C) then
       write(*, *) B
   else
       write(*, *) A
   end if
end program ABC_075_A_OneoutofThree