use warnings;
use strict;

my $str1 = q/It is a guide to action which ensures that the military always obey the commands of the party./;
my $str2 = q/It is a guide to action that ensures that the military will forever heed Party commands is a guide./;

my $n = 0;
while ( $str1 =~ /(?=(\S+\s+\S+\s+\S+))/g ) {
    my $t1 = $1;
    while ( $str2 =~ /($t1)/g ) {
        print $1;
        $n++;
        }
    }

print "No of matching is : $n";