Zookeeper is buying a carton of fruit to feed his pet wabbit. The fruits are a sequence of apples and oranges, which is represented by a binary string s_1s_2… s_n of length n. 1 represents an apple and 0 represents an orange.

Since wabbit is allergic to eating oranges, Zookeeper would like to find the longest contiguous sequence of apples. Let f(l,r) be the longest contiguous sequence of apples in the substring s_{l}s_{l+1}… s_{r}. 

Help Zookeeper find ∑_{l=1}^{n} ∑_{r=l}^{n} f(l,r), or the sum of f across all substrings.

Input

The first line contains a single integer n (1 ≤ n ≤ 5 ⋅ 10^5).

The next line contains a binary string s of length n (s_i ∈ \{0,1\}) 

Output

Print a single integer: ∑_{l=1}^{n} ∑_{r=l}^{n} f(l,r). 

Examples

Input


4
0110


Output


12


Input


7
1101001


Output


30


Input


12
011100011100


Output


156

Note

In the first test, there are ten substrings. The list of them (we let [l,r] be the substring s_l s_{l+1} … s_r):

  * [1,1]: 0 
  * [1,2]: 01 
  * [1,3]: 011 
  * [1,4]: 0110 
  * [2,2]: 1 
  * [2,3]: 11 
  * [2,4]: 110 
  * [3,3]: 1 
  * [3,4]: 10 
  * [4,4]: 0 



The lengths of the longest contiguous sequence of ones in each of these ten substrings are 0,1,2,2,1,2,2,1,1,0 respectively. Hence, the answer is 0+1+2+2+1+2+2+1+1+0 = 12.
import java.io.*;
import java.util.*;

public class Main{
	static void main() throws Exception{
		int n=sc.nextInt();
		char[]in=sc.nextLine().toCharArray();
		long ans=0;
		int[]last=new int[n+1];
		Arrays.fill(last, -1);
		long sum=0;
		for(int i=0;i<n;) {
			if(in[i]=='0') {
				i++;
				ans+=sum;
				continue;
			}
			int start=i;
			while(i<n && in[i]=='1')i++;
			int end=i-1;
			int len=end-start+1;
			for(int cur=1;cur<=len;cur++) {
				int delta=start-last[cur];
				sum+=delta;
				last[cur]=end;
				start++;
				end--;
				ans+=sum;
			}
		}
		pw.println(ans);
	}
	public static void main(String[] args) throws Exception{
		sc=new MScanner(System.in);
		pw = new PrintWriter(System.out);
//		int tc=1;
//		tc=sc.nextInt();
//		while(tc-->0)
			main();
		pw.flush();
	}
	static PrintWriter pw;
	static MScanner sc;
	static class MScanner {
		StringTokenizer st;
		BufferedReader br;
		public MScanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}
	 
		public MScanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}
	 
		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}
		public int[] intArr(int n) throws IOException {
	        int[]in=new int[n];for(int i=0;i<n;i++)in[i]=nextInt();
	        return in;
		}
		public long[] longArr(int n) throws IOException {
	        long[]in=new long[n];for(int i=0;i<n;i++)in[i]=nextLong();
	        return in;
		}
		public int[] intSortedArr(int n) throws IOException {
	        int[]in=new int[n];for(int i=0;i<n;i++)in[i]=nextInt();
	        shuffle(in);
	        Arrays.sort(in);
	        return in;
		}
		public long[] longSortedArr(int n) throws IOException {
	        long[]in=new long[n];for(int i=0;i<n;i++)in[i]=nextLong();
	        shuffle(in);
	        Arrays.sort(in);
	        return in;
		}
		public Integer[] IntegerArr(int n) throws IOException {
	        Integer[]in=new Integer[n];for(int i=0;i<n;i++)in[i]=nextInt();
	        return in;
		}
		public Long[] LongArr(int n) throws IOException {
	        Long[]in=new Long[n];for(int i=0;i<n;i++)in[i]=nextLong();
	        return in;
		}
		public String nextLine() throws IOException {
			return br.readLine();
		}
	 
		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}
	 
		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}
	 
		public char nextChar() throws IOException {
			return next().charAt(0);
		}
	 
		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}
	 
		public boolean ready() throws IOException {
			return br.ready();
		}
	 
		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
		
	}
	static void shuffle(int[]in) {
		for(int i=0;i<in.length;i++) {
			int idx=(int)(Math.random()*in.length);
			int tmp=in[i];
			in[i]=in[idx];
			in[idx]=tmp;
		}
	}
	static void shuffle(long[]in) {
		for(int i=0;i<in.length;i++) {
			int idx=(int)(Math.random()*in.length);
			long tmp=in[i];
			in[i]=in[idx];
			in[idx]=tmp;
		}
	}
}