You are given a permutation p of n integers 1, 2, ..., n (a permutation is an array where each element from 1 to n occurs exactly once).

Let's call some subsegment p[l, r] of this permutation special if p_l + p_r = max _{i = l}^{r} p_i. Please calculate the number of special subsegments.

Input

The first line contains one integer n (3 ≤ n ≤ 2 ⋅ 10^5).

The second line contains n integers p_1, p_2, ..., p_n (1 ≤ p_i ≤ n). All these integers are pairwise distinct.

Output

Print the number of special subsegments of the given permutation.

Examples

Input


5
3 4 1 5 2


Output


2


Input


3
1 3 2


Output


1

Note

Special subsegments in the first example are [1, 5] and [1, 3].

The only special subsegment in the second example is [1, 3].
//package educational.round75;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Set;

public class E {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	SegmentTreeRMQPos st;
	int[] a;
	int ans = 0;
	
	void solve()
	{
		int n = ni();
		a = na(n);
		int[] ia = new int[n];
		for(int i = 0;i < n;i++)ia[i] = -a[i];
		st = new SegmentTreeRMQPos(ia);
		ans = 0;
		dfs(0, n);
		out.println(ans);
	}
	
	Set<Integer> dfs(int l, int r)
	{
		if(l >= r)return new HashSet<>();
		int max = -st.min(l, r);
		int maxpos = st.minpos;
		Set<Integer> L = dfs(l, maxpos);
		Set<Integer> R = dfs(maxpos+1, r);
		if(L.size() > R.size()){
			Set<Integer> D = L; L = R;R = D;
		}
		for(int x : L){
			if(R.contains(max-x)){
				ans++;
			}
		}
		R.addAll(L);
		R.add(max);
		return R;
	}
	
	public static class SegmentTreeRMQPos {
		public int M, H, N;
		public int[] st;
		public int[] pos;
		
		public SegmentTreeRMQPos(int n)
		{
			N = n;
			M = Integer.highestOneBit(Math.max(N-1, 1))<<2;
			H = M>>>1;
			st = new int[M];
			pos = new int[M];
			for(int i = 0;i < N;i++)pos[H+i] = i;
			Arrays.fill(st, 0, M, Integer.MAX_VALUE);
			for(int i = H-1;i >= 1;i--)propagate(i);
		}
		
		public SegmentTreeRMQPos(int[] a)
		{
			N = a.length;
			M = Integer.highestOneBit(Math.max(N-1, 1))<<2;
			H = M>>>1;
			st = new int[M];
			pos = new int[M];
			for(int i = 0;i < N;i++){
				st[H+i] = a[i];
				pos[H+i] = i;
			}
			Arrays.fill(st, H+N, M, Integer.MAX_VALUE);
			for(int i = H-1;i >= 1;i--)propagate(i);
		}
		
		public void update(int pos, int x)
		{
			st[H+pos] = x;
			for(int i = (H+pos)>>>1;i >= 1;i >>>= 1)propagate(i);
		}
		
		private void propagate(int i)
		{
			if(st[2*i] <= st[2*i+1]){
				st[i] = st[2*i];
				pos[i] = pos[2*i];
			}else{
				st[i] = st[2*i+1];
				pos[i] = pos[2*i+1];
			}
		}
		
		public int minpos;
		public int minval;
		
		public int minx(int l, int r){
			minval = Integer.MAX_VALUE;
			minpos = -1;
			if(l >= r)return minval;
			while(l != 0){
				int f = l&-l;
				if(l+f > r)break;
				int v = st[(H+l)/f];
				if(v < minval || v == minval && pos[(H+l)/f] < minpos){
					minval = v;
					minpos = pos[(H+l)/f];
				}
				l += f;
			}
			
			while(l < r){
				int f = r&-r;
				int v = st[(H+r)/f-1];
				if(v < minval || v == minval && pos[(H+r)/f-1] < minpos){
					minval = v;
					minpos = pos[(H+r)/f-1];
				}
				r -= f;
			}
			return minval;
		}
		
		public int min(int l, int r){ 
			minpos = -1;
			minval = Integer.MAX_VALUE;
			min(l, r, 0, H, 1);
			return minval;
		}
		
		private void min(int l, int r, int cl, int cr, int cur)
		{
			if(l <= cl && cr <= r){
				if(st[cur] < minval){
					minval = st[cur];
					minpos = pos[cur];
				}
			}else{
				int mid = cl+cr>>>1;
				if(cl < r && l < mid)min(l, r, cl, mid, 2*cur);
				if(mid < r && l < cr)min(l, r, mid, cr, 2*cur+1);
			}
		}
	}

	
	void run() throws Exception
	{
		is = oj ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		tr(System.currentTimeMillis()-s+"ms");
	}
	
	public static void main(String[] args) throws Exception { new E().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private boolean oj = System.getProperty("ONLINE_JUDGE") != null;
	private void tr(Object... o) { if(!oj)System.out.println(Arrays.deepToString(o)); }
}
