#include <bits/stdc++.h>
using namespace std;

int yue[15] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

bool rn(int a) {
	if (a % 100 != 0) {
		if (a % 4 == 0) return true;
	} else {
		if (a % 400 == 0) return true;
	}
	return false;
}

int panduan(int nian) {
	int a = 11;
	for (int i = 1; i <= 10; i++) {
		a += yue[i];
	}
	if (rn(nian) == true) a += 1;
	return a;
}

int main() {
	int a, b, ans = 0;
	cin >> a >> b;
	for (int i = a; i <= b; i++) {
		//cout <<  i << "年有" << panduan(i) << "天" << endl;
		if (panduan(i) % 7 == 0) ans++;
	}
	cout << ans;
	return 0;
}

哪里有问题啊...