import sys
input = lambda : sys.stdin.readline().rstrip()
sys.setrecursionlimit(max(1000, 10**9))
write = lambda x: sys.stdout.write(x+"\n")


n = int(input())
a = list(map(int, input().split()))
inf = 10**15
dp = [-inf]*10
dp[0] = 0
for i in range(n):
    nl = [inf]*10
    nl[0] = 0
    for j in range(10):
        nl[(j+a[i])%10] = max(dp[(j+a[i])%10], dp[j] + 1)
    dp = nl
#     print(dp)
if dp[0]>-inf:
    ans = dp[0]
else:
    ans = 0
print(ans)