sub base8{
    my($s) = @_;
    my $i = 0;
    my $ret = 0;
    for(split//,$s){
        $ret+=$_;
        $ret*=2;
        $i++
    }
    $ret/2;
}
$_=<>;chomp;
s/A/1010/g;
s/B/1011/g;
s/C/1100/g;
s/D/1101/g;
s/E/1110/g;
s/F/1111/g;
while($_){
    $a = base8(substr($_,-3));
    $h{$a}++;
    $_=substr($_,0,-3);
}
$max = 0;
for $i(keys %h){ $max=$h{$i}if$max<$h{$i};}
for $i(sort keys %h){push @ans, $i if$max==$h{$i};}
print join " ",@ans,$/;