n = int(input())
a = list(map(int,input().split()))

d = [-float("Inf")]*10
d[0] = 0
for x in a:
    dnext = [-float("Inf")]*10
    for j in range(10):
        dnext[j] = max(dnext[j],d[j])
        dnext[(x+j)%10] = max(dnext[(x+j)%10],d[j] + 1)
        
    d = dnext
print(d[0])