#!/usr/bin/perl -Tw
use warnings;
use strict;

local $/ = ""; # paragraph mode

while ( my $para = <> ) {
    next unless $para =~ s/^=head(\d)\s+//;

    my $level = $1;
    chomp $para;

    print " " x (($level-1)*4) if $level > 1;
    print "$para\n";
}