program enter_data
    implicit none
    integer::i,n
    real::mark,sum,average
    sum = 0.0
    
    print *, "input Number os student"
    read *, n
    do i=1,n
        read *,mark
        sum = sum+mark
    end do
    average = sum/real(n)
    print *,'average=',average
end program enter_data