#include <iostream>
#include <cstdio>

using namespace std;

int main() {
	int n, k;
	int win = 0;

	for (int i = 0; i < 1000; i++) {
		cin >> n >> k;
		if (n % (k + 1) != 1) {
			win++;
		}
	}
	cout << win << endl;
	return 0;
}