#!/usr/bin/perl -w

use strict;

my $n = 0;
my $Sx = 0;
my $Sxx = 0;
my $Sy = 0;
my $Sxy = 0;

while (<STDIN>) {
	$_ =~ /^(\S+) (\S+)$/ or die "cannot parse input";
	my $x = $1;
	my $y = $2;

	$n++;
	$Sx += $x;
	$Sxx += $x*$x;
	$Sy += $y;
	$Sxy += $x*$y;
}

my $nVar =  $n * $Sxx - $Sx * $Sx;
my $m    = ($n * $Sxy - $Sx * $Sy) / $nVar;
my $a    = ($Sxx  * $Sy - $Sxy * $Sx) / $nVar;

print <<"EOI";

n   = $n
Sx  = $Sx
Sxx = $Sxx
Sy  = $Sy
Sxy = $Sxy

m   = $m
a   = $a
EOI