source_code: import java.util.Scanner;
  
  public class A {
      public static void main(String[] args) {
          new A().solve();
      }
      
      public void solve() {
          Scanner sc = new Scanner(System.in);
          int n = sc.nextInt();
          int t = sc.nextInt();
          float[] left = new float[n];
          float[] right = new float[n];
          for (int i=0; i<n; ++i) {
              int c = sc.nextInt();
              int w = sc.nextInt();
              left[i] = (float) (c - (float) w * 1.0 / 2);
              right[i] = (float) (c + (float) w * 1.0 / 2);
          }
          for (int i=0; i<n; ++i)
              for (int j=i+1; j<n; ++j)
                  if (left[j] < left[i]) {
                      float tmp = left[i];
                      left[i] = left[j];
                      left[j] = tmp;
                      tmp = right[i];
                      right[i] = right[j];
                      right[j] = tmp;
                  }
          int res = 2;
          for (int i=1; i<n; ++i) {
              float dis = left[i] - right[i-1];
              if (Math.abs(dis - t) < 0.000001)
                  res ++;
              if ((dis - t) > 0.000001)
                  res += 2;
          }
          System.out.println(res);
      }
  }
  