Largest prime factor in RUBY

Largest prime factor in RUBY

Can someone please tell me what im doing wrong.
x=13195, n=2, max=n
for n in (2...x)
if (x%n==0)
prime=true
for y in (1...n)
if n%y==0
prime=false
end
y+=1
end
if prime
max=n
end
end
n+=1
end
puts "#{max}"