Hands that shed innocent blood!

There are n guilty people in a line, the i-th of them holds a claw with length Li. The bell rings and every person kills some of people in front of him. All people kill others at the same time. Namely, the i-th person kills the j-th person if and only if j < i and j ≥ i - Li.

You are given lengths of the claws. You need to find the total number of alive people after the bell rings.

Input

The first line contains one integer n (1 ≤ n ≤ 106) — the number of guilty people.

Second line contains n space-separated integers L1, L2, ..., Ln (0 ≤ Li ≤ 109), where Li is the length of the i-th person's claw.

Output

Print one integer — the total number of alive people after the bell rings.

Examples

Input

4
0 1 0 10


Output

1


Input

2
0 0


Output

2


Input

10
1 1 3 0 0 0 2 1 0 3


Output

3

Note

In first sample the last person kills everyone in front of him.
import java.io.*;
import java.util.*;

public class Competitive_2 {
	
	public static void main(String[] args) {
		FastReader in = new FastReader();
		int n = in.nextInt();
		int l[] = new int[n];
		
		for(int i=0; i<n; i++)
			l[i] = in.nextInt();
		
		boolean alive[] = new boolean[n];
		Arrays.fill(alive, true);
		
		int ans = 0;
		
		for(int i=n-1; i>=0; i--){
			if(alive[i]){
				ans++;
				int limit = i-l[i];
				for(int j=i-1; j>=0&&j>=limit; j--){
					alive[j] = false;
					if(j-l[j]<limit)
						limit = Math.max(j-l[j], 0);
				}
			}
		}
		
		System.out.println(ans);
	}
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            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 nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
	
	
}
