#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
from queue import PriorityQueue
import bisect
import heapq

def input():
    return sys.stdin.readline()[:-1]

sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """# paste here...
# """
# sys.stdin = io.StringIO(_INPUT)



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

    dp = [[-10**10 for _ in range(10)] for _ in range(N+1)]

    # dp[i][k] := i枚以下のカードで，総和の余りがkになる取り方の枚数の総和
    dp[0][0] = 0

    for i in range(1, N+1):
        a = A[i-1] % 10
        for k in range(10):
            dp[i][k] = max(dp[i-1][k], dp[i-1][k-a] + 1)

    print(dp[N][0])

if __name__ == '__main__':
    main()