#include<bits/stdc++.h>
#include<iostream>
using namespace std;
using LL = long long;
using P = pair<int,int>;
using Graph = vector<vector<int>>;
const int INF = 1 << 29;
const long long LINF = 1LL << 60;
#define all(x) (x).begin(), (x).end()
#define rep(i,n) for(int i = 0; i < (n); ++i)
template<class T>void chmin(T&a, T b){if(a > b) a = b;}
template<class T>void chmax(T&a, T b){if(a < b) a = b;}


int main(){
	int N; cin >> N; 
	vector<int> A(N);
	for(int i = 0; i < N; ++i) cin >> A[i];

	vector<vector<int>> dp(N+1, vector<int>(10,0));
	for(int i = 0; i < N; ++i){
		if(dp[i][A[i]%10]==0) dp[i+1][A[i]%10] = 1;
		for(int j = 0; j < 10; ++j){
			if(dp[i][j]!=0){
				   chmax(dp[i+1][(j+A[i])%10], dp[i][j]+1);
				   chmax(dp[i+1][j], dp[i][j]);
			}
		}
	}

	cout << dp[N][0] << endl;
}