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.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.InputMismatchException;

public class TaskB
{
	public static void main(String[] args)
	{
		new TaskB(System.in, System.out);
	}

	static class Solver implements Runnable
	{
		int n;
		int[] lengths;
		InputReader in;
		PrintWriter out;

		void solve() throws IOException
		{
			n = in.nextInt();
			lengths = in.nextIntArray(n);

			int cnt = 0;
			int min = Integer.MAX_VALUE;

			for (int i = n - 1; i >= 0; i--)
			{
				if (min > i)
					cnt++;

				min = Math.min(min, i - lengths[i]);
			}

			out.println(cnt);
		}

		public Solver(InputReader in, PrintWriter out)
		{
			this.in = in;
			this.out = out;
		}

		@Override
		public void run()
		{
			try
			{
				solve();
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
		}

	}

	static class InputReader
	{
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read()
		{
			if (numChars == -1)
				throw new InputMismatchException();

			if (curChar >= numChars)
			{
				curChar = 0;
				try
				{
					numChars = stream.read(buf);
				}
				catch (IOException e)
				{
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}

			return buf[curChar++];
		}

		public int nextInt()
		{
			int c = read();

			while (isSpaceChar(c))
				c = read();

			int sgn = 1;

			if (c == '-')
			{
				sgn = -1;
				c = read();
			}

			int res = 0;

			do
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();

				res *= 10;
				res += c & 15;

				c = read();
			} while (!isSpaceChar(c));

			return res * sgn;
		}

		public int[] nextIntArray(int arraySize)
		{
			int array[] = new int[arraySize];

			for (int i = 0; i < arraySize; i++)
				array[i] = nextInt();

			return array;
		}

		public boolean isSpaceChar(int c)
		{
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		public void close()
		{
			try
			{
				stream.close();
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
		}

		public InputReader(InputStream stream)
		{
			this.stream = stream;
		}

	}

	public TaskB(InputStream inputStream, OutputStream outputStream)
	{
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Thread thread = new Thread(null, new Solver(in, out), "TaskB", 1 << 29);

		try
		{
			thread.start();
			thread.join();
		}
		catch (InterruptedException e)
		{
			e.printStackTrace();
		}
		finally
		{
			in.close();
			out.flush();
			out.close();
		}
	}

}

