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

my $n = $*IN.get;
my @a = $*IN.get.words;
my $mx = 0;
my $ans = 0;

for @a {
	my $v = $_.Int;
	if $v > $mx {
		$mx = $v;
	} elsif $ans < $v && $v < $mx {
		$ans = $v;
	}
}

say $ans;