#include <stdio.h>

int main()
{
	int N;
	scanf("%d", &N);
	
	int n, ans = 0;
	for (n = 1; n <= N; n++) if (n % 10 == 8 || n / 10 % 10 == 8 || n / 100 % 10 == 8) ans++;
	printf("%d\n", ans);
	fflush(stdout);
	return 0;
}