import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;
import java.util.Stack;

class Main {
	public static void main(String[] $) {
		new Main().run();
	}
	
	void run() {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int[] dp=new int[10];
		Arrays.fill(dp, -N);
		dp[0]=0;
		for (int i=0;i<N;++i) {
			int a=sc.nextInt()%10;
			int[] ndp=Arrays.copyOf(dp, dp.length);
			for (int j=0;j<10;++j) {
				ndp[(j+a)%10]=Math.max(ndp[(j+a)%10], dp[j]+1);
			}
			dp=ndp;
		}
		System.out.println(dp[0]);
		
	}
	
	void tr(Object...objects) {System.out.println(Arrays.deepToString(objects));}
}