import sys
import pypyjit
import itertools
import heapq
import math
from collections import deque, defaultdict
import bisect

input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)
pypyjit.set_param('max_unroll_recursion=-1')


def index_lt(a, x):
    'return largest index s.t. A[i] < x or -1 if it does not exist'
    return bisect.bisect_left(a, x) - 1


def index_le(a, x):
    'return largest index s.t. A[i] <= x or -1 if it does not exist'
    return bisect.bisect_right(a, x) - 1


def index_gt(a, x):
    'return smallest index s.t. A[i] > x or len(a) if it does not exist'
    return bisect.bisect_right(a, x)


def index_ge(a, x):
    'return smallest index s.t. A[i] >= x or len(a) if it does not exist'
    return bisect.bisect_left(a, x)


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

INF = 1 << 30
dp = [[-INF for _ in range(10)] for _ in range(N + 1)]
dp[0][0] = 0
for i in range(N):
    for j in range(10):
        n = (j + A[i]) % 10
        dp[i + 1][n] = max(dp[i + 1][n], dp[i][j] + 1)
        dp[i + 1][j] = max(dp[i + 1][j], dp[i][j])
print(dp[N][0])