#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> P;
int INF = 1e18+7;
int mod = 1e9+7;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
int dp[200005][15];
signed main() {
    int N;
    cin >> N;
    for(int i = 0; i < N; i++) {
        int A;
        cin >> A;
        for(int j = 0; j < 10; j++) {
            dp[i+1][j] = max(dp[i+1][j],dp[i][j]);
            if(j == 0 || dp[i][j]) {
                dp[i+1][(j+A)%10] = max(dp[i+1][(j+A)%10],dp[i][j]+1);
            }
        }
    }
    cout << dp[N][0] << endl;
}