#use strict;
use warnings;

my $File1 = <<FILE;
13
34
32
20
43
FILE

my $File2 = <<FILE;
22
15
27
33
48
65
34
FILE

my $File3 = <<FILE;
18
20
22
45
44
32
12
26
FILE

my @data;

for my $file (\$File1, \$File2, \$File3) {
    open my $fIn, '<', $file or die "Can't open $file: $!\n";
    
    push @data, [];
    
    while (<$fIn>) {
        chomp;
        push @{$data[-1]}, $_;
    }
}

while (grep {@$_} @data) {
    printf "%s\n", join "\t", map {$_ // ''} map {shift @$_} @data;
}