You are given a string s=s_1s_2... s_n of length n, which only contains digits 1, 2, ..., 9.

A substring s[l ... r] of s is a string s_l s_{l + 1} s_{l + 2} … s_r. A substring s[l ... r] of s is called even if the number represented by it is even. 

Find the number of even substrings of s. Note, that even if some substrings are equal as strings, but have different l and r, they are counted as different substrings.

Input

The first line contains an integer n (1 ≤ n ≤ 65000) — the length of the string s.

The second line contains a string s of length n. The string s consists only of digits 1, 2, ..., 9.

Output

Print the number of even substrings of s.

Examples

Input


4
1234


Output


6

Input


4
2244


Output


10

Note

In the first example, the [l, r] pairs corresponding to even substrings are: 

  * s[1 ... 2]
  * s[2 ... 2]
  * s[1 ... 4]
  * s[2 ... 4]
  * s[3 ... 4]
  * s[4 ... 4] 



In the second example, all 10 substrings of s are even substrings. Note, that while substrings s[1 ... 1] and s[2 ... 2] both define the substring "2", they are still counted as different substrings.
import java.io.*;
import java.util.*;
import java.math.*;
import java.lang.*;
 
import static java.lang.Math.*;

public class Cf82 implements Runnable 
{
	static class InputReader 
	{
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;
		private SpaceCharFilter filter;
		private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		public InputReader(InputStream stream) 
		{
			this.stream = stream;
		}
        
		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 String nextLine()
        {
		String str = "";
		try
		{
			str = br.readLine();
		}
		catch (IOException e)
		{
			e.printStackTrace();
		}
		return str;
	}
        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 - '0';
			c = read();
		}
		while (!isSpaceChar(c)); 
        
		return res * sgn;
	}
        
        public long nextLong() 
        {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		long res = 0;
            
		do 
		{
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		}
		while (!isSpaceChar(c));
			return res * sgn;
        }
        
        public double nextDouble() 
        {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		double res = 0;
		while (!isSpaceChar(c) && c != '.') 
		{
			if (c == 'e' || c == 'E')
				return res * Math.pow(10, nextInt());
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		}
		if (c == '.') 
		{
			c = read();
			double m = 1;
			while (!isSpaceChar(c))
			{
				if (c == 'e' || c == 'E')
					return res * Math.pow(10, nextInt());
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				m /= 10;
				res += (c - '0') * m;
				c = read();
			}
		}
		return res * sgn;
        }
    
        public String readString() 
        {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do 
		{
			res.appendCodePoint(c);
			c = read();
		} 
		while (!isSpaceChar(c));
            
		return res.toString();
        }
     
	public boolean isSpaceChar(int c) 
	{
		if (filter != null)
			return filter.isSpaceChar(c);
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}
	public String next()
	{
		return readString();
	}
        
	public interface SpaceCharFilter
	{
		public boolean isSpaceChar(int ch);
	}
	}
	public static void main(String args[]) throws Exception 
	{
		new Thread(null, new Cf82(),"Main",1<<27).start();
	}
	public void run()
	{
		InputReader sc = new InputReader(System.in);
		PrintWriter w = new PrintWriter(System.out);
		int n=sc.nextInt();
		String s = new String();
		s=sc.next();
		int i,j,k,count=0;
		for(i=0;i<n;i++)
		{
			if((int)s.charAt(i)%2==0)
			{
				count=count+(i+1);
			}
		}
		w.println(count);
		System.out.flush();
		w.close();
	}
}