#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ALL(A) A.begin(),A.end()
#define RALL(A) A.rbegin(),A.rend()
typedef long long ll;
typedef pair<ll,ll> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
const ll MOD=1000000007;
const ll LINF=1ll<<60;
const int INF=1<<30;
int dx[]={1,0,-1,0,1,-1,1,-1};
int dy[]={0,1,0,-1,1,-1,-1,1};


int main(){
    int n;cin >> n;
    vector<ll> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        a[i] %= 10;
    }
    vector<vector<ll>> dp(n+1,vector<ll> (10, -LINF));
    dp[0][0] = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < 10; j++) {
            chmax(dp[i+1][(j+a[i])%10],dp[i][j] + 1);
            chmax(dp[i+1][j],dp[i][j]);
        }
    }
    cout << dp[n][0] << endl;
    return 0;
}