program aoc22day2

    implicit none
    integer :: ios
    integer, parameter :: xmasunit = 99
    integer, allocatable :: calories(:)
    integer :: n, i, meal, m
    character(len=999) :: line

    open(unit=xmasunit, file='input.txt', iostat=ios)
    if ( ios /= 0 ) stop "Christmas is over"

    n = 0

    do
        read(xmasunit, '(A)', iostat=ios) line
        if (ios /= 0) exit
        if (len_trim(line) == 0 ) n = n + 1
    end do

    print*, "There exists:", n, "elves"

    allocate(calories(n+1))
    rewind(xmasunit)
    meal = 0
    i = 0

    do
        read(xmasunit, '(A)', iostat=ios) line
        if (ios /= 0) exit
        if (len_trim(line) == 0 ) then
            i = i + 1
            calories(i) = meal
            meal = 0
        else
            read (line,'(I10)') m
            meal = meal + m
        endif
    end do
    calories(n+1) = meal

    print*, "The highest amount of calories carried by an elf is: ", maxval(calories)

    close(xmasunit)

end program aoc22day2