#include <bits/stdc++.h>
//#include "atcoder/all"
typedef long long int ll;
using namespace std;
// using namespace atcoder;
#define MAXN 200005
int dp[MAXN][10];
int main() {
    int n;
    cin >> n;
    ll a[n + 1];
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    for (int i = 0; i < MAXN; i++) {
        for (int j = 0; j < 10; j++) {
            dp[i][j] = -1000;
        } 
    }
    dp[0][0] = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j < 10; j++) {
            dp[i][(j + a[i]) % 10] = max(dp[i - 1][j] + 1, max(dp[i - 1][(j + a[i]) % 10], dp[i][(j + a[i]) % 10]));
        }
    }
    cout << dp[n][0] << endl;
    return 0;
}