#include "bits/stdc++.h"

//#include <atcoder/all>

using namespace std;
//using namespace atcoder;

//#define int long long
#define ll long long

ll INF = (1LL << 60);
int mod = 1000000007;

using P = pair<int, int>;
ll dp[200010][10];
signed main() {
	int N; cin >> N;
	vector<ll>A(N); for (int i = 0; i < N; i++)cin >> A[i];
	for (int i = 0; i < 200010; i++) {
		for (int j = 0; j < 10; j++) {
			dp[i][j] = -INF;
		}
	}
	dp[0][0] = 0;
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < 10; j++) {
			dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);

			dp[i + 1][(j + A[i]) % 10] = max(dp[i + 1][(j + A[i]) % 10], dp[i][j] + 1);
		
		}
	}
	ll ans = dp[N][0];
	cout << ans << endl;
	return 0;
}