include <stdio.h>

include <math.h>

int main() { // freopen("perfect.in", "r", stdin); // freopen("perfect.out", "w", stdout);

long long a, b, a1, b1, j, i, c = 0, flag;
scanf("%lld%lld", &a, &b);
a1 = sqrt(a);
b1 = sqrt(b);
for (long long i = a1; i <= b1; i++) {
	long long t = i * i;
	int sum = 0;
	if (a <= t && t <= b)	{
		while (t > 0) {
			sum = sum + t % 10;
			t = t / 10;
		}
		int flag = 0;
		if (sum < 2) {
			flag = 1;
		}

		for (int j = 2; j <= sum - 1; j++) {
			if ( sum % j == 0) {
				flag = 1;
				break;

			}

		}

		if (flag == 0) {
			c++;
		}
	}

}

printf("%lld", c);
return 0;

}