#include<stdio.h>
#include<math.h>
int main()
{
	int L, R, count = 0;
	scanf("%d %d", &L, &R);
	for (; L <= R; L++)
	{
		if (L % 10 == 2)
			count++;
		if (L / 10 == 2)
			count++;
	}
	printf("%d", count);
	return 0;
}