#!/usr/bin/perl
use v5.35.0;

# Parse input map

my ($width, @edge, @obstacle, $dir, $start);
my $pos = 0;
while (<>) {
	$width ||= length;
	for (split //) {
		$edge[$pos] = /\s/;
		$obstacle[$pos] = /#/;
		if ((my $i = index('^>v<', $_)) >= 0) {
			$dir = $i;
			$start = $pos;
		}
		$pos++;
	}
}
my @step = (-$width, 1, $width, -1);

# Walk the guard's route

my %visited = ();
$pos = $start;
for (;;) {
	$visited{$pos} = 1;		# Mark route
	$pos += $step[$dir];		# Advance

	last unless 0 <= $pos < @edge;	# Escape
	last if $edge[$pos];
	
	if ($obstacle[$pos]) {		# Obstacle?
		$pos -= $step[$dir];	# Retreat
		$dir++, $dir &= 3	# Turn right
	}
}

say scalar keys %visited;