#!/usr/bin/awk -f

BEGIN { sum = 0 }

{
    split($2, start, ":")
    split($3, end, ":")
    start_mins = start[1]*60+start[2]
    end_mins = end[1] * 60 + end[2]
    delta = (end_mins - start_mins) / 60
    print $1,$2,$3,delta,substr($0, index($0,$4))
    sum = sum + delta
}

END { print "sum:",sum }