#include <bits/stdc++.h>
using namespace std;

int main(){
  long long N, sum = 0;
  cin >> N;
  long long A[N];
  for(int i = 0; i < N; i++) {
    cin >> A[i];
    A[i] %= 10LL;
    sum += A[i];
  }
  long long dp[N+10][20];
  for(int i = 0; i < N+10; i++) {
    for(int j = 0; j < 20; j++) {
      if (j == 0) {
        dp[i][j] = 0;
      }else {
        dp[i][j] = 1e9;
      }
    }
  }
  for (int i = 0; i < N; i++) {
    for (int j = 0; j <= 9; j++) {
      dp[i + 1][(j + A[i]) % 10LL] = min(dp[i + 1][(j + A[i]) % 10LL], dp[i][j] + 1LL);
      dp[i + 1][j] = min(dp[i + 1][j], dp[i][j]);
    }
  }
  cout << N - dp[N][sum % 10LL] << endl;
  return 0;
}