#include<stdio.h>
int main()
{
	int n;
	scanf("%d", &n);
	int i, j;
	int a[200005];
	for (i = 0; i < n; i++)
		scanf("%d", &a[i]);
	int dp[200005][10];
	for (j = 0; j < 10; j++)
		dp[0][j] = 0;
	dp[0][a[0] % 10] = 1;
	for (i = 1; i < n; i++)
	{
		for (j = 0; j < 10; j++)
			dp[i][j] = dp[i - 1][j];
		for (j = 0; j < 10; j++)
			if (dp[i - 1][j] > 0 && dp[i][(j + a[i]) % 10] < dp[i - 1][j] + 1)
				dp[i][(j + a[i]) % 10] = dp[i - 1][j] + 1;
	}
	printf("%d\n", dp[n - 1][0]);
	return 0;
}