require \'prime\'
primes = Array.new
counter = ARGV[0].to_i
counter = 30 if counter == 0
(2..counter).to_a.each { |x|
if Prime.prime? x then
primes << x
end
}
x = primes
y = primes
print \' \'
x.each {|i| print "%-3d " % i}
print "\\n "
x.each {|i| print \'---- \'}
print "\\n"
y.each do |j|
print "%-3d| " % j
x.each {|i| print "%-3d " % (i*j)}
print "\\n"
end