program main
    use,intrinsic :: iso_fortran_env
    implicit none
    integer(int32):: a,b,c

    read*, a,b,c
    if (a==b) then
        print'(i0)', c
    else if(b==c) then
        print'(i0)', a
    else
        print'(i0)', b
    end if
end program main