Write a function to find the size of the largest subset of a list of numbers so that every pair is divisible.
def largest_subset(a):
	n = len(a)
	dp = [0 for i in range(n)]
	dp[n - 1] = 1; 
	for i in range(n - 2, -1, -1):
		mxm = 0;
		for j in range(i + 1, n):
			if a[j] % a[i] == 0 or a[i] % a[j] == 0:
				mxm = max(mxm, dp[j])
		dp[i] = 1 + mxm
	return max(dp)