#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)

int main() {
	int dp[10];
	rep(i, 10) dp[i] = -10000000; dp[0] = 0;
	int buf[10];
	int N; scanf("%d", &N);
	rep(i, N) {
		int a; scanf("%d", &a);
		rep(j, 10) buf[(j + a) % 10] = dp[j] + 1;
		rep(j, 10) dp[j] = max(dp[j], buf[j]);
	}
	printf("%d\n", dp[0]);
	return 0;
}