#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; }