The string t_1t_2 ... t_k is good if each letter of this string belongs to at least one palindrome of length greater than 1.

A palindrome is a string that reads the same backward as forward. For example, the strings A, BAB, ABBA, BAABBBAAB are palindromes, but the strings AB, ABBBAA, BBBA are not.

Here are some examples of good strings: 

  * t = AABBB (letters t_1, t_2 belong to palindrome t_1 ... t_2 and letters t_3, t_4, t_5 belong to palindrome t_3 ... t_5); 
  * t = ABAA (letters t_1, t_2, t_3 belong to palindrome t_1 ... t_3 and letter t_4 belongs to palindrome t_3 ... t_4); 
  * t = AAAAA (all letters belong to palindrome t_1 ... t_5); 



You are given a string s of length n, consisting of only letters A and B.

You have to calculate the number of good substrings of string s.

Input

The first line contains one integer n (1 ≤ n ≤ 3 ⋅ 10^5) — the length of the string s.

The second line contains the string s, consisting of letters A and B.

Output

Print one integer — the number of good substrings of string s.

Examples

Input


5
AABBB


Output


6


Input


3
AAA


Output


3


Input


7
AAABABB


Output


15

Note

In the first test case there are six good substrings: s_1 ... s_2, s_1 ... s_4, s_1 ... s_5, s_3 ... s_4, s_3 ... s_5 and s_4 ... s_5.

In the second test case there are three good substrings: s_1 ... s_2, s_1 ... s_3 and s_2 ... s_3.
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.Random;
import java.io.PrintWriter;
/*
    Solution Created: 19:37:29 08/10/2019
    Custom Competitive programming helper.
*/
public class Main {
	public static void solve(Reader in, Writer out) {
		int n = in.nextInt();
		char[] a = in.next().toCharArray();
		long ans = get(n);
		{
			int[] lastIdxA = new int[n];
			int[] lastIdxB = new int[n];
			lastIdxA[n-1] = a[n-1]=='A'?n-1:n;
			lastIdxB[n-1] = a[n-1]=='B'?n-1:n;
			for(int i = n-2; i>=0; i--) {
				lastIdxA[i] = a[i]=='A'?i:lastIdxA[i+1];
				lastIdxB[i] = a[i]=='B'?i:lastIdxB[i+1];
			}
			for(int i = 0; i<n-1; i++) {
				if(a[i]!=a[i+1]) {
					if(a[i]=='A') {
						ans-=lastIdxA[i+1]-i-1;
					}else {
						ans-=lastIdxB[i+1]-i-1;
					}
				}
			}
		}
		for(int i = 0; i<n/2; i++){
			char tmp = a[i];
			a[i] = a[n-i-1];
			a[n-i-1] = tmp;
		}
		{
			int[] lastIdxA = new int[n];
			int[] lastIdxB = new int[n];
			lastIdxA[n-1] = a[n-1]=='A'?n-1:n;
			lastIdxB[n-1] = a[n-1]=='B'?n-1:n;
			for(int i = n-2; i>=0; i--) {
				lastIdxA[i] = a[i]=='A'?i:lastIdxA[i+1];
				lastIdxB[i] = a[i]=='B'?i:lastIdxB[i+1];
			}
			for(int i = 0; i<n-1; i++) {
				if(a[i]!=a[i+1]) {
					if(a[i]=='A') {
						ans-=lastIdxA[i+1]-i-1;
					}else {
						ans-=lastIdxB[i+1]-i-1;
					}
					ans++;
				}
			}
		}
		out.println(ans);
	}
	public static long get(long n) {
		return n*(n-1)/2;
	}
	public static void main(String[] args) {
		Reader in = new Reader();
		Writer out = new Writer();
		solve(in, out);
		out.exit();
	}

static class Graph {
	private ArrayList<Integer> con[];
	private boolean[] visited;

	public Graph(int n) {
		con = new ArrayList[n];
		for (int i = 0; i < n; ++i)
			con[i] = new ArrayList();
		visited = new boolean[n];
	}

	public void reset() {
		Arrays.fill(visited, false);
	}

	public void addEdge(int v, int w) {
		con[v].add(w);
	}

	public void dfs(int cur) {
		visited[cur] = true;
		for (Integer v : con[cur]) {
			if (!visited[v]) {
				dfs(v);
			}
		}
	}

	public void bfs(int cur) {
		Queue<Integer> q = new LinkedList<>();
		q.add(cur);
		visited[cur] = true;
		while (!q.isEmpty()) {
			cur = q.poll();
			for (Integer v : con[cur]) {
				if (!visited[v]) {
					visited[v] = true;
					q.add(v);
				}
			}
		}
	}
}

static class Reader {
	static BufferedReader br;
	static StringTokenizer st;
	private int charIdx = 0;
	private String s;

	public Reader() {
		this.br = new BufferedReader(new InputStreamReader(System.in));
	}

	public int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = nextInt();
		return a;
	}

	public double[] nd(int n) {
		double[] a = new double[n];
		for (int i = 0; i < n; i++)
			a[i] = nextDouble();
		return a;
	}

	public char nextChar() {
		if (s == null || charIdx >= s.length()) {
			if (st == null || !st.hasMoreTokens())
				try {
					readLine();
				} catch (Exception e) {
				}
			s = st.nextToken();
			charIdx = 0;
		}
		return s.charAt(charIdx++);
	}

	public long[] nl(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nextLong();
		return a;
	}

	public char[] nca() {
		return next().toCharArray();
	}

	public String[] nS(int n) {
		String[] a = new String[n];
		for (int i = 0; i < n; i++)
			a[i] = next();
		return a;
	}

	public int nextInt() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return Integer.parseInt(st.nextToken());
	}

	public double nextDouble() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return Double.parseDouble(st.nextToken());
	}

	public Long nextLong() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return Long.parseLong(st.nextToken());
	}

	public String next() {
		if (st == null || !st.hasMoreTokens())
			try {
				readLine();
			} catch (Exception e) {
			}
		return st.nextToken();
	}

	public static void readLine() {
		try {
			st = new StringTokenizer(br.readLine());
		} catch (Exception e) {
		}
	}
}

static class Sort {
	static Random random = new Random();
	public static void sortArray(int[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
	public static void sortArray(long[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
	public static void sortArray(String[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
	public static void sortArray(char[] s) {
        shuffle(s);
        Arrays.sort(s);
    }
    private static void shuffle(int[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            int t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
    private static void shuffle(long[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            long t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
    private static void shuffle(String[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            String t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
    private static void shuffle(char[] s) {
        for (int i = 0; i < s.length; ++i) {
            int j = random.nextInt(i + 1);
            char t = s[i];
            s[i] = s[j];
            s[j] = t;
        }
    }
}

static class Util{
	    static boolean isPrime(int n) { 
	        if (n <= 1) return false; 
	        if (n <= 3) return true; 
	        if (n % 2 == 0 || n % 3 == 0) return false; 
	        for (int i = 5; i * i <= n; i = i + 6) 
	            if (n % i == 0 || n % (i + 2) == 0) 
	            return false; 
	        return true; 
	    }
		public static int upperBound(long[] a, long v) {
			int l=0, h=a.length-1, ans = -1;
			while(l<h) {
				int mid = (l+h)/2;
				if(a[mid]<=v) {
					ans = mid;
					l = mid+1;
				}else h = mid-1;
			}
			return ans;
		}
		public static int lowerBound(long[] a, long v) {
			int l=0, h=a.length-1, ans = -1;
			while(l<h) {
				int mid = (l+h)/2;
				if(v<=a[mid]) {
					ans = mid;
					h = mid-1;
				}else l = mid-1;
			}
			return ans;
		}
	    public static boolean[] getSieve(int n) {
	        boolean[] isPrime = new boolean[n+1];
	        for (int i = 2; i <= n; i++) isPrime[i] = true;
	        for (int i = 2; i*i <= n; i++) if (isPrime[i]) 
	                for (int j = i; i*j <= n; j++) isPrime[i*j] = false;
	        return isPrime;
	    }
	    public static int gcd(int a, int b) { 
	        if (a == 0) 
	            return b; 
	        return gcd(b%a, a); 
	    }
		public static long modAdd(long a, long b, long mod) {
			return (a%mod+b%mod)%mod;
		}
		public static long modMul(long a, long b, long mod) {
			return ((a%mod)*(b%mod))%mod;
		}
		public static void dbg(Object... o) { 
			System.out.println(Arrays.deepToString(o)); 
		}
	}

static class Writer {
	private PrintWriter pw;
	public Writer(){
		pw = new PrintWriter(System.out);
	}
	
	public void printArray(int[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
	}
	public void printlnArray(int[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
		pw.println();
	}
	public void printArray(long[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
	}
	public void printlnArray(long[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
		pw.println();
	}
	public void print(Object o) {
		pw.print(o.toString());
	}
	public void println(Object o) {
		pw.println(o.toString());
	}
	public void println() {
		pw.println();
	}
	public void flush() {
		pw.flush();
	}
	public void exit() {
		pw.close();
	}
}
}
