#!/usr/bin/perl -w
use strict;

# Build a regex of "\d\d\d:|\s\d\d:|\s\s\d:|\s\s\s"
my $str = join ":|", map { '\s'x$_ . '\d'x(3-$_) } 0 .. 3;

while (<>){
    s/^$str//; # Remove anything that matches regex from start of line
    print;
}