dxhsmwqc:第三题AC的 n, k = [int(x) for x in input().strip().split()]
nums = [int(x)%3 for x in input().strip().split()]
def cal(nums, k):
m = min(nums.count(1), nums.count(2))
if k<=m:
return k
else:
mm = max(nums.count(1) - m, nums.count(2) - m)
mm = mm//3
if (k-m)//2 <= mm:
return m + (k-m)//2
else:
return m + mm
print(cal(nums, k) + nums.count(0))