Divide with a loop in Fortran

I'm trying to create a program that divides my number between two until I reach the unit and that's where the program ends.

multiplication program
    implicit none
    integer :: a
    integer :: b
    integer :: i

        print *, "Write two natural numbers between 0 and 100:"

    read *, a, b

        do while ((a <= 100) .and. (b <= 100))
            write (*, *) "The numbers meet the required conditions"
            read (*, *) a, b
            a = a / 2; i = i / 2
        end do
end program multiplication

Thanks in advance.