#include <algorithm>
#include <iostream>
using namespace std;
int main() {
    int n; cin >> n;
    const int INF = 1<<30;
    int dp[2][10] = {};
    fill(dp[0], dp[0]+10, -INF);
    fill(dp[1], dp[1]+10, -INF);
    int cur = 0, prev = 1;
    dp[prev][0] = 0;
    for (int i = 1; i < 10; i++) dp[prev][i] = -INF;
    for (int i = 0; i < n; i++) {
        int a; cin >> a;
        for (int i = 0; i < 10; i++) {
            int j = (i + a) % 10;
            if (dp[prev][i] >= 0)
                dp[cur][j] = max(dp[prev][j], 1 + dp[prev][i]);
            else
                dp[cur][j] = dp[prev][j];
        }
        // for (int j = 0; j < 10; j++) cerr << dp[cur][j] << " "; cerr << endl;
        swap(cur, prev);
    }
    cout << max(0, dp[prev][0]) << endl;
}