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.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Queue;

public class Main {

	public static void main(String[] args) {
		new Main();
	}

	public Main() {
		FastScanner fs = new FastScanner();
		java.io.PrintWriter out = new java.io.PrintWriter(System.out);
		solve(fs, out);
		out.flush();
	}

	public void solve(FastScanner fs, java.io.PrintWriter out) {
		int n = fs.nextInt();
		char[] s = fs.next().toCharArray();
		int[] sum = new int[n + 1], rev = new int[n + 1];
		for (int i = 0;i < n;++ i) {
			sum[i + 1] = s[i] == '1' ? sum[i] + 1 : 0;
			rev[n - i - 1] = s[n - i - 1] == '1' ? rev[n - i] + 1 : 0;
		}
		ArrayList<Queue<Integer>> pq = new ArrayList<>(n);
		for (int i = 0;i <= n;++ i) pq.add(new ArrayDeque<>());
		for (int i = 0;i <= n;++ i) pq.get(sum[i]).add(i);
		for (int i = 0;i <= n;++ i) pq.get(i).add(n+1);
		long ans = 0;
		for (int i = 1;i <= n;++ i) {
			if (sum[i] == 0) continue;
			pq.get(rev[i - 1]).poll();
			long len = pq.get(rev[i - 1]).peek() - i;
			ans += i * len;
		}
		out.println(ans);
	}
}

class FastScanner {

	private final java.io.InputStream in = System.in;
	private final byte[] buffer = new byte[8192];
	private int ptr = 0;
	private int buflen = 0;

	private boolean hasNextByte() {
		if (ptr < buflen) return true;
		ptr = 0;
		try {
			buflen = in.read(buffer);
		} catch (java.io.IOException e) {
			e.printStackTrace();
		}
		return buflen > 0;
	}

	private byte readByte() {
		return hasNextByte() ? buffer[ptr++ ] : -1;
	}

	private static boolean isPrintableChar(byte c) {
		return 32 < c || c < 0;
	}

	private static boolean isNumber(int c) {
		return '0' <= c && c <= '9';
	}

	public boolean hasNext() {
		while (hasNextByte() && !isPrintableChar(buffer[ptr]))
			ptr++ ;
		return hasNextByte();
	}

	public String next() {
		if (!hasNext()) throw new java.util.NoSuchElementException();
		StringBuilder sb = new StringBuilder();
		byte b;
		while (isPrintableChar(b = readByte()))
			sb.appendCodePoint(b);
		return sb.toString();
	}

	public final char nextChar() {
		if (!hasNext()) throw new java.util.NoSuchElementException();
		return (char)readByte();
	}

	public final long nextLong() {
		if (!hasNext()) throw new java.util.NoSuchElementException();
		long n = 0;
		try {
			byte b = readByte();
			if (b == '-') {
				while (isNumber(b = readByte()))
					n = n * 10 + '0' - b;
				return n;
			} else if (!isNumber(b)) throw new NumberFormatException();
			do
				n = n * 10 + b - '0';
			while (isNumber(b = readByte()));
		} catch (java.util.NoSuchElementException e) {}
		return n;
	}

	public final int nextInt() {
		if (!hasNext()) throw new java.util.NoSuchElementException();
		int n = 0;
		try {
			byte b = readByte();
			if (b == '-') {
				while (isNumber(b = readByte()))
					n = n * 10 + '0' - b;
				return n;
			} else if (!isNumber(b)) throw new NumberFormatException();
			do
				n = n * 10 + b - '0';
			while (isNumber(b = readByte()));
		} catch (java.util.NoSuchElementException e) {}
		return n;
	}

	public double nextDouble() {
		return Double.parseDouble(next());
	}
}

class Arrays {

	public static void sort(final int[] array) {
		int l, min = 0xFFFFFFFF, max = 0;
		for (l = 0; l < array.length; ++l) {
			int i = array[l];
			min &= i;
			max |= i;
			if ((i & 0x80000000) == 0) break;
		}
		for (int r = l + 1; r < array.length; ++r) {
			int i = array[r];
			min &= i;
			max |= i;
			if ((i & 0x80000000) != 0) {
				array[r] = array[l];
				array[l++ ] = i;
			}
		}
		int use = min ^ max, bit = Integer.highestOneBit(use & 0x7FFFFFFF);
		if (bit == 0) return;
		sort(array, 0, l, use, bit);
		sort(array, l, array.length, use, bit);
	}

	private static void sort(final int[] array, final int left, final int right, final int use, int digit) {
		if (right - left <= 96) {
			for (int i = left + 1; i < right; ++i) {
				int tmp = array[i], tmp2, j;
				for (j = i; j > left && (tmp2 = array[j - 1]) > tmp; --j)
					array[j] = tmp2;
				array[j] = tmp;
			}
			return;
		}
		int l = left;
		while (l < right && (array[l] & digit) == 0)
			++l;
		for (int r = l + 1; r < right; ++r) {
			int i = array[r];
			if ((i & digit) == 0) {
				array[r] = array[l];
				array[l++ ] = i;
			}
		}
		if ((digit = Integer.highestOneBit(use & digit - 1)) == 0) return;
		sort(array, left, l, use, digit);
		sort(array, l, right, use, digit);
	}

	public static void sort(final long[] array) {
		int l;
		long min = 0xFFFFFFFFFFFFFFFFL, max = 0;
		for (l = 0; l < array.length; ++l) {
			long i = array[l];
			min &= i;
			max |= i;
			if ((i & 0x8000000000000000L) == 0) break;
		}
		for (int r = l + 1; r < array.length; ++r) {
			long i = array[r];
			min &= i;
			max |= i;
			if ((i & 0x8000000000000000L) != 0) {
				array[r] = array[l];
				array[l++ ] = i;
			}
		}
		long use = min ^ max, bit = Long.highestOneBit(use & 0x7FFFFFFFFFFFFFFFL);
		if (bit == 0) return;
		sort(array, 0, l, use, bit);
		sort(array, l, array.length, use, bit);
	}

	private static void sort(final long[] array, final int left, final int right, final long use, long digit) {
		if (right - left <= 96) {
			for (int i = left + 1, j; i < right; ++i) {
				long tmp = array[i], tmp2;
				for (j = i; j > left && (tmp2 = array[j - 1]) > tmp; --j)
					array[j] = tmp2;
				array[j] = tmp;
			}
			return;
		}
		int l = left;
		while (l < right && (array[l] & digit) == 0)
			++l;
		for (int r = l + 1; r < right; ++r) {
			long i = array[r];
			if ((i & digit) == 0) {
				array[r] = array[l];
				array[l++ ] = i;
			}
		}
		if ((digit = Long.highestOneBit(use & digit - 1)) == 0) return;
		sort(array, left, l, use, digit);
		sort(array, l, right, use, digit);
	}
}

class IntMath {

	public static int gcd(int a, int b) {
		while (a != 0)
			if ((b %= a) != 0) a %= b;
			else return a;
		return b;
	}

	public static int gcd(int... array) {
		int ret = array[0];
		for (int i = 1; i < array.length; ++i)
			ret = gcd(ret, array[i]);
		return ret;
	}

	public static long gcd(long a, long b) {
		while (a != 0)
			if ((b %= a) != 0) a %= b;
			else return a;
		return b;
	}

	public static long gcd(long... array) {
		long ret = array[0];
		for (int i = 1; i < array.length; ++i)
			ret = gcd(ret, array[i]);
		return ret;
	}

	public static long lcm(long a, long b) {
		return a / gcd(a, b) * b;
	}

	public static int pow(int a, int b) {
		int ans = 1;
		for (int mul = a; b > 0; b >>= 1, mul *= mul)
			if ((b & 1) != 0) ans *= mul;
		return ans;
	}

	public static long powLong(long a, long b) {
		long ans = 1;
		for (long mul = a; b > 0; b >>= 1, mul *= mul)
			if ((b & 1) != 0) ans *= mul;
		return ans;
	}

	public static int pow(int a, int b, int mod) {
		if (b < 0) b = b % (mod - 1) + mod - 1;
		long ans = 1;
		for (long mul = a; b > 0; b >>= 1, mul = mul * mul % mod)
			if ((b & 1) != 0) ans = ans * mul % mod;
		return (int)ans;
	}

	public static int floorsqrt(long n) {
		return (int)Math.sqrt(n + 0.1);
	}

	public static int ceilsqrt(long n) {
		return n <= 1 ? (int)n : (int)Math.sqrt(n - 0.1) + 1;
	}
}
