import sys
input = sys.stdin.readline
import copy

N=int(input())
A=list(map(int,input().split()))

DP=[-1]*10
DP[0]=0

for a in A:
    NDP=copy.deepcopy(DP)
    for i in range(10):
        if DP[i]!=-1:
            NDP[(i+a)%10]=max(DP[(i+a)%10],DP[i]+1)
    DP=NDP

print(DP[0])