import copy

n = int(input())
A = list(map(lambda x:int(x)%10,input().split()))

dp = [0]*10

#print("A =",A)

for j,a in enumerate(A):
    if j == 0:
        dp[a] = 1
        continue
    cp = copy.deepcopy(dp)
    for i in range(10):
        if cp[i] != 0:
            dp[(i+a)%10] = max(cp[(i+a)%10],cp[i]+1)
    #print(dp)
    
print(dp[0])