#!/usr/bin/perl
# yukicoder My Practice
# author: Leonardone @ NEETSDKASU

my $n = $*IN.get;
my @a = $*IN.get.words.map({ .Int });
my $mx = 0;
my $ans = 0;

for @a {
	$mx = max($mx, $_);
	if $ans < $_ && $_ < $mx {
		$ans = $_;
	}
}

say $ans;