#!/usr/bin/fish

set lines (cat input)
set pos 0
set trees 0
for val in $lines
	set width (string length $val)
	set char (string sub -s (math $pos + 1) -l 1 $val)
	set pos (math "($pos + 3) % $width")

	if test "$char" = "#"
		set trees (math $trees + 1)
	end
end

echo "total nr of trees is $trees"