using System;
using System.Collections.Generic;
using System.Linq;

namespace No249
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			int winCount = 0;
			for (int i = 0; i < 1000; i++) {
				var line = Console.ReadLine ().Split (' ').Select (v => Convert.ToInt32 (v)).ToArray();
				var n = line [0];
				var k = line [1];
				if (n % (k + 1) == 1) {
				} else {
					winCount++;
				}
			}
			Console.WriteLine (winCount.ToString ());
		}
	}
}