#!/usr/bin/perl -w

my $n = <STDIN>;
my $sum = 0;
for (my $i = 0; $i < $n; $i = $i + 1){
	my $val = <STDIN>;
	$sum = $sum + $val;
} # end for

$res = sprintf("%.10f\n",$sum);
print $res . '\n';