import sys
import collections

sys.setrecursionlimit(10 ** 8)

input = sys.stdin.readline


def main():
    N = int(input())
    A = [int(x) for x in input().split()]

    dp = [[-float("inf")] * 10 for j in range(N + 1)]

    dp[0][0] = 0
    for i in range(N):
        a = A[i - 1]
        for j in range(10):
            if dp[i][j] == -float("inf"):
                continue
            dp[i + 1][(j + a) % 10] = max(dp[i + 1][(j + a) % 10], dp[i][j] + 1)
            dp[i + 1][j] = max(dp[i + 1][j], dp[i][j])

    print(dp[N][0])





    
    

if __name__ == '__main__':
    main()