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.*;
 public class Solution {
	 
	//static int ans;
	static String str="";
	static int dp[];
	public static void main(String[] args) throws Exception
    {
		FastReader fr=new FastReader();
        int n=fr.nextInt();
        String s=fr.next();long c=0;
        for(int i=0;i<s.length();i++) {
        	if(Integer.parseInt(s.substring(i,i+1))%2==0) {
        		c+=(i+1);
        	}
        }
        System.out.println(c);
        
		
    }	
	
	
	 
public static String lcs(String a,String b) {
		int dp[][]=new int[a.length()+1][b.length()+1];
		for(int i=0;i<=a.length();i++)
		{
			for(int j=0;j<=b.length();j++)
			{
				if(i==0||j==0)
					dp[i][j]=0;
			}
		}
		
		for(int i=1;i<=a.length();i++)
		{
			for(int j=1;j<=b.length();j++)
			{
				if(a.charAt(i-1)==b.charAt(j-1))
					dp[i][j]=1+dp[i-1][j-1];
				else
					dp[i][j]=Math.max(dp[i-1][j],dp[i][j-1]);
			}
		}
		
		int i=a.length();
		int j=b.length();
		String lcs="";
		while(i>0&&j>0)
		{
			if(a.charAt(i-1)==b.charAt(j-1)) {
				lcs=a.charAt(i-1)+lcs;
				i--;
				j--;
			}
			else 
			{
				if(dp[i-1][j]>dp[i][j-1])
					i--;
				else
					j--;
			}
		}
		
		return lcs;
            
	}
	
	 
	 
	 
	 public static long facto(long n) {
		 if(n==1||n==0)
			 return 1;
		 return n*facto(n-1);
	 }
	 public static long gcd(long n1,long n2) {
		 if (n2 == 0) {
		        return n1;
		    }
		    return gcd(n2, n1 % n2);
	}
	 public static boolean isPali(String s) {
		 int i=0;
		 int j=s.length()-1;
		 while(i<=j) {
			 if(s.charAt(i)!=s.charAt(j))
				 return false;
			 i++;
			 j--;
		 }
		 return true;
	 }
	 public static String reverse(String s) {
		 String res="";
		 for(int i=0;i<s.length();i++) {
			 res+=s.charAt(i);
		 }
		 return res;
	 }
	
		
	 
	 public static int bsearch(long suf[],long val) {
		 int i=0;
		 int j=suf.length-1;
		 while(i<=j) {
			 int mid=(i+j)/2;
			 if(suf[mid]==val)
				 return mid;
			 else if(suf[mid]<val)
				 j=mid-1;
			 else
				 i=mid+1;
		 }
		 return -1;
	 }
	 
	 
	 
	
	 
	 
	public static int[] getFreq(String s) {
		int a[]=new int[26];
		for(int i=0;i<s.length();i++) {
			a[s.charAt(i)-'a']++;
		}
		return a;
		
	}
	 
	 public static boolean isPrime(int n) {
		 
		 for(int i=2;(i*i)<=n;i++) {
			 if(n%i==0)
				 return false;
		 }
		 return true;
	 }
            	  
             
             
    }
class Pair{
	long i;
	long j;
	
	Pair(long num,long freq){
		this.i=num;
		
		this.j=freq;
	}
	
}

	
	 
	
	

	 
 
  

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;
    }
}

