$ perl -Mstrict -wE ' > open my $fh, q{<}, \ < 0 a b h > 1 - r z > 3 u - u > 4 r x r > 5 r t r > 6 r r r > 7 r r r > 8 r r r > EOD > > my $count; > while ( <$fh> ) > { > my( $seq, @cols ) = split; > $count ++ if tr{r}{} == scalar @cols; > } > say $count;' 3 $