#! perl -slw
use strict;

our $N //= 2;
our $M //= 1e6;

die "N < 1 makes no sense.\n\n" if $N < 1;
die "M must be equal to N or larger than N.\n\n" if $M < $N;

my $size = ( $M + 1 ) / $N;

my @ranges;
for ( my $i = 0; $i < $M; $i += $size ) {
    my ( $j, $k ) = ( int $i, int ($i + $size) );
    push @ranges, [ $j, $k - 1, $k - $j  ];
}

( printf "%2d : from %7d to %7d (%7d)\n",
        $_,
        @{ $ranges[ $_ ] }
) for 0 .. $#ranges;

__END__