In a factory, there are N robots placed on a number line. Robot i is placed at coordinate X_i and can extend its arms of length L_i in both directions, positive and negative.

We want to remove zero or more robots so that the movable ranges of arms of no two remaining robots intersect. Here, for each i (1 \leq i \leq N), the movable range of arms of Robot i is the part of the number line between the coordinates X_i - L_i and X_i + L_i, excluding the endpoints.

Find the maximum number of robots that we can keep.

Constraints

* 1 \leq N \leq 100,000
* 0 \leq X_i \leq 10^9 (1 \leq i \leq N)
* 1 \leq L_i \leq 10^9 (1 \leq i \leq N)
* If i \neq j, X_i \neq X_j.
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N
X_1 L_1
X_2 L_2
\vdots
X_N L_N


Output

Print the maximum number of robots that we can keep.

Examples

Input

4
2 4
4 3
9 3
100 5


Output

3


Input

2
8 20
1 10


Output

1


Input

5
10 1
2 1
4 1
6 1
8 1


Output

5
import java.io.*;
import java.util.*;
import java.math.*;
import java.awt.Point;
 
public class Main {
	//static final long MOD = 998244353L;
	//static final long INF = -1000000000000000007L;
	static final long MOD = 1000000007L;
	//static final int INF = 1000000007;

	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		int N = sc.ni();
		int[][] ranges = new int[N][2];
		ArrayList<Long> nums = new ArrayList<Long>();
		for (int i = 0; i < N; i++) {
			int X = sc.ni();
			int L = sc.ni();
			ranges[i][0] = X-L;
			ranges[i][1] = X+L;
			nums.add((long)ranges[i][0]);
			nums.add((long)ranges[i][1]);
		}
		ranges = sort(ranges);
		Collections.sort(nums);
		HashMap<Long,Integer> hm = new HashMap<Long,Integer>();
		for (int i = 0; i < nums.size(); i++) {
			hm.put(nums.get(i),i);
		}
		for (int i = 0; i < N; i++) {
			ranges[i][0] = hm.get((long)ranges[i][0]);
			ranges[i][1] = hm.get((long)ranges[i][1]);
		}
		
		int[] dp = new int[N+1];
		SegmentTree st = new SegmentTree(2*N);
		for (int i = 0; i < N; i++) {
			dp[i+1] = Math.max(dp[i],1+(int)st.maxQuery(1, 1, 2*N,1,ranges[i][0]+1));
			int cur = (int)st.maxQuery(1, 1, 2*N, ranges[i][1]+1,ranges[i][1]+1);
			int add = Math.max(dp[i+1]-cur,0);
			st.add(1, 1, 2*N, ranges[i][1]+1,ranges[i][1]+1,add);
		}
		pw.println(dp[N]);
		pw.close();
	}
	
	static class SegmentTree {

		public long[][] ranges;

		public SegmentTree(int N) {
			ranges = new long[4*N+1][4];
		}

		//range update nums[updateL..updateR] += val;
		public void add(int n, int L, int R, int updateL, int updateR, long val) {
			push(n,L,R);
			if (updateL <= L && R <= updateR) {
				//fully contained
				ranges[n][3] += val;
				push(n,L,R);
				return;
			} else if (L>updateR || R<updateL || L==R) {
				//not contained at all or leaf
				return;
			}
			add(2*n,L,(L+R)/2,updateL,updateR,val); 
			add(2*n+1,(L+R)/2+1,R,updateL,updateR,val);
			ranges[n][1] = Math.min(ranges[2*n][1],ranges[2*n+1][1]);
			ranges[n][2] = Math.max(ranges[2*n][2],ranges[2*n+1][2]);
			ranges[n][0] = ranges[2*n][0] + ranges[2*n+1][0];
		}

		public long minQuery(int n, int L, int R, int Lq, int Rq) {
			push(n,L,R);
			if (Lq <= L && R <= Rq) {
				return ranges[n][1];
			} else if (R < Lq || Rq < L || L==R) {
				return 1000000000000007L;
			} else {
				return Math.min(minQuery(2*n,L,(L+R)/2,Lq,Rq),minQuery(2*n+1,(L+R)/2+1,R,Lq,Rq));
			}
		}

		public long maxQuery(int n, int L, int R, int Lq, int Rq) {
			push(n,L,R);
			if (Lq <= L && R <= Rq) {
				return ranges[n][2];
			} else if (R < Lq || Rq < L || L==R) {
				return -1L;
			} else {
				return Math.max(maxQuery(2*n,L,(L+R)/2,Lq,Rq),maxQuery(2*n+1,(L+R)/2+1,R,Lq,Rq));
			}
		}

		public long sumQuery(int n, int L, int R, int Lq, int Rq) {
			push(n,L,R);
			if (Lq <= L && R <= Rq) {
				return ranges[n][0];
			} else if (R < Lq || Rq < L || L==R) {
				return 0L;
			} else {
				return (sumQuery(2*n,L,(L+R)/2,Lq,Rq) + sumQuery(2*n+1,(L+R)/2+1,R,Lq,Rq));
			}
		}

		public void push(int n, int L, int R) {
			ranges[n][1] += ranges[n][3];
			ranges[n][2] += ranges[n][3];
			ranges[n][0] += (R-L+1)*ranges[n][3];

			if (L < R) {
				ranges[2*n][3] += ranges[n][3];
				ranges[2*n+1][3] += ranges[n][3];
			}

			ranges[n][3] = 0;
		}
	}
	
	public static long dist(long[] p1, long[] p2) {
		return (Math.abs(p2[0]-p1[0])+Math.abs(p2[1]-p1[1]));
	}
	
	//Find the GCD of two numbers
	public static long gcd(long a, long b) {
		if (a < b) return gcd(b,a);
		if (b == 0)
			return a;
		else
			return gcd(b,a%b);
	}
	
	//Fast exponentiation (x^y mod m)
	public static long power(long x, long y, long m) { 
		long ans = 1;
		x %= m;
		while (y > 0) { 
			if(y % 2 == 1) 
				ans = (ans * x) % m; 
			y /= 2;  
			x = (x * x) % m;
		} 
		return ans; 
	}
	
	public static int[][] shuffle(int[][] array) {
		Random rgen = new Random();
		for (int i = 0; i < array.length; i++) {
		    int randomPosition = rgen.nextInt(array.length);
		    int[] temp = array[i];
		    array[i] = array[randomPosition];
		    array[randomPosition] = temp;
		}
		return array;
	}
	
    public static int[][] sort(int[][] array) {
    	//Sort an array (immune to quicksort TLE)
 
		Arrays.sort(array, new Comparator<int[]>() {
			  @Override
        	  public int compare(int[] arr1, int[] arr2) {
				  return arr1[0]-arr2[0]; //ascending order
	          }
		});
		return array;
	}
    
    public static long[][] sort(long[][] array) {
    	//Sort an array (immune to quicksort TLE)
		Random rgen = new Random();
		for (int i = 0; i < array.length; i++) {
		    int randomPosition = rgen.nextInt(array.length);
		    long[] temp = array[i];
		    array[i] = array[randomPosition];
		    array[randomPosition] = temp;
		}
		Arrays.sort(array, new Comparator<long[]>() {
			  @Override
        	  public int compare(long[] arr1, long[] arr2) {
				  //return 0;
				  if (arr1[0] < arr2[0]) {
					  return -1;
				  } else if (arr1[1] > arr2[1]) {
					  return 1;
				  } else {
					  return 0;
				  }
	          }
		});
		return array;
	}
    
    static class FastScanner { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastScanner() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine());
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int ni() { 
            return Integer.parseInt(next()); 
        } 
  
        long nl() { 
            return Long.parseLong(next()); 
        } 
  
        double nd() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() { 
            String str = ""; 
            try { 
                str = br.readLine(); 
            } catch (IOException e) {
                e.printStackTrace(); 
            } 
            return str;
        }
    }
}