program main
    use iso_fortran_env
    implicit none

    character(1) :: txt
    character(27) :: cap
    integer(int32) :: i
    cap = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

    i = 0
    read(*,*) txt
    i = index(cap, txt)

    if (i == 0) then
        print *, "a"
    else
        print *, "A"
    endif

end program main