use feature ":5.14";
use warnings FATAL => qw(all);
use strict;
use Data::Dump qw(dump);

my @RouterOutput = split /\n/, << 'END';
1 AAAA BBBB CCCC
2 AAAA BBBB CCCC
3 AAAA BBBB CCCC
4 AAAA BBBB CCCC
END

for(@RouterOutput[0..2])
 {say "@{[split]}[0,3,2,1]" if $_;
 }