package contest210129;

import java.io.*;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.Queue;

public class F3 {
	InputStream is;
	FastWriter out;

	String INPUT = "";

	long l(int a, int b)
	{
		return (long)a<<32|b;
	}

	public void solve()
	{
		int n = ni();
		int[] a = na(n);
		Datum[] ds = new Datum[n];
		for(int i = 0;i < n;i++){
			long[] rs = {1L<<32|n+1};
			for(int j = Math.max(i-2, 0);j <= i && j+2 < n;j++){
				if(i-j == 0){
					if(a[j] > a[j+1]) {
//						rs = and(rs, new int[][]{{a[j+1]+1, a[j+2]}, {a[j+2]+1, n+1}});
						rs = and(rs, new long[]{l(a[j+1]+1, a[j+2]), l(a[j+2]+1, n+1)});
					}else{
						rs = and(rs, new long[]{l(1, a[j+2]), l(a[j+2]+1, a[j+1])});
//						rs = and(rs, new int[][]{{1, a[j+2]}, {a[j+2]+1, a[j+1]}});
					}
				}else if(i-j == 1){
//					rs = and(rs, new int[][]{{1, Math.min(a[j], a[j+2])}, {Math.max(a[j], a[j+2])+1, n+1}});
					rs = and(rs, new long[]{l(1, Math.min(a[j], a[j+2])), l(Math.max(a[j], a[j+2])+1, n+1)});
				}else if(i-j == 2){
					if(a[j] > a[j+1]) {
						rs = and(rs, new long[]{l(a[j+1]+1, a[j]), l(a[j]+1, n+1)});
					}else{
						rs = and(rs, new long[]{l(1, a[j]), l(a[j]+1, a[j+1])});
					}
				}
			}
			ds[i] = new Datum(rs, a[i]);
		}

		long ans = dfs(0, n, ds);

		for(int i = 0;i < n;i++){
			for(int j = i+1;j <= i+2 && j < n;j++){
				{int d = a[i]; a[i] = a[j]; a[j] = d;}
				boolean ok = true;
				for(int k = Math.max(0, i-2);k <= j && k+2 < n;k++){
					if(!kdmt(a[k], a[k+1], a[k+2]))ok = false;
				}
				if(ok){
					ans++;
				}
				{int d = a[i]; a[i] = a[j]; a[j] = d;}
			}
		}
		out.println(ans);
	}

	static class Datum
	{
		long[] rs;
		int v;

		public Datum(long[] rs, int v) {
			this.rs = rs;
			this.v = v;
		}
	}

	int[] ft = new int[200004];
	Datum[] temp = new Datum[200004];

	long dfs(int l, int r, Datum[] ds) {
		if (r - l <= 3) {
			Arrays.sort(ds, l, r, (x, y) -> x.v - y.v);
			return 0L;
		}
		int h = l + r >> 1;
		long ret = 0;
		for (int i = Math.max(l, h - 2); i < h; i++) {
			for (int j = h; j < h + 2 && j < r; j++) {
				if (j - i <= 2) {
					Datum L = ds[i], R = ds[j];
					if (isin(R.v, L.rs) && isin(L.v, R.rs)) {
						ret--;
					}
				}
			}
		}

		ret += dfs(l, h, ds) + dfs(h, r, ds);

		int pp = 0;
		for(int i = h;i < r;i++){
			long[] tar = ds[i].rs;
			pp += 2*tar.length;
		}
		long[] es = new long[pp];
		int p = 0;
		for(int i = h;i < r;i++){
			long[] tar = ds[i].rs;
			for(long t : tar){
				es[p++] = t>>>32<<32|ds[i].v<<1|0;
				es[p++] = (long)((int)t)<<32|ds[i].v<<1|1;
			}
		}
		Arrays.sort(es);

//		int[][] es = new int[pp][];
//		int p = 0;
//		for(int i = h;i < r;i++){
//			int[][] tar = ds[i].rs;
//			for(int[] t : tar){
//				es[p++] = new int[]{t[0], ds[i].v, -1};
//				es[p++] = new int[]{t[1], ds[i].v, 1};
//			}
//		}
//		Arrays.sort(es, (x, y) -> x[0] - y[0]);

		int q = 0;
		for(long e : es){
			while(q < h-l && ds[q+l].v < e>>>32){
				for(long u : ds[q+l].rs){
					addFenwick(ft, (int)(u>>>32), (int)u, 1);
				}
				q++;
			}
			ret += ((e&1)*2-1) * sumFenwick(ft, ((int)e)>>>1);
		}
		while(q > 0){
			for(long u : ds[q-1+l].rs){
				addFenwick(ft, (int)(u>>>32), (int)u, -1);
			}
			q--;
		}

		{
			for (int i = l; i < r; i++) {
				temp[i] = ds[i];
			}
			int i = l, j = h, o = l;
			for (; i < h && j < r; ) {
				if (ds[i].v <= ds[j].v) {
					ds[o++] = temp[i++];
				} else {
					ds[o++] = temp[j++];
				}
			}
			while (i < h) ds[o++] = temp[i++];
			while (j < r) ds[o++] = temp[j++];
		}


		return ret;
	}



	boolean isin(int x, long[] rs)
	{
		for(long r : rs){
			if(r>>>32 <= x && x < (int)r)return true;
		}
		return false;
	}

	public static int sumFenwick(int[] ft, int i)
	{
		int sum = 0;
		for(i++;i > 0;i -= i&-i)sum += ft[i];
		return sum;
	}

	public static void addFenwick(int[] ft, int l, int r, int v)
	{
		addFenwick(ft, l, v);
		addFenwick(ft, r, -v);
	}

	public static void addFenwick(int[] ft, int i, int v)
	{
		if(v == 0 || i < 0)return;
		int n = ft.length;
		for(i++;i < n;i += i&-i)ft[i] += v;
	}


	public static int lowerBound(int[] a, int v){ return lowerBound(a, 0, a.length, v); }
	public static int lowerBound(int[] a, int l, int r, int v)
	{
		if(l > r || l < 0 || r > a.length)throw new IllegalArgumentException();
		int low = l-1, high = r;
		while(high-low > 1){
			int h = high+low>>>1;
			if(a[h] >= v){
				high = h;
			}else{
				low = h;
			}
		}
		return high;
	}


	public static long[] and(long[] a, long[] b)
	{
		long[] rs = new long[a.length + b.length];
		int p = 0;
		for(int i = 0, j = 0;i < a.length && j < b.length;){
			long from = Math.max(a[i]>>>32, b[j]>>>32);
			long to = Math.min((int)a[i], (int)b[j]);
			if(from < to)rs[p++] = from<<32|to;

			if((int)a[i] < (int)b[j]){
				i++;
			}else{
				j++;
			}
		}
		return Arrays.copyOf(rs, p);
	}

	boolean kdmt(int[] a)
	{
		int n = a.length;
		for(int i = 0;i < n-2;i++){
			if(!kdmt(a[i], a[i+1], a[i+2])){
				return false;
			}
		}
		return true;
	}

	boolean kdmt(int a, int b, int c)
	{
		if(a == b)return false;
		if(c == b)return false;
		if(a == c)return false;
		return a < b && b > c || a > b && b < c;
	}


	public static void main(String[] args) {
		new F3().run();
	}

	public void run()
	{
//		int n = 200000, m = 99999;
//		Random gen = new Random();
//		StringBuilder sb = new StringBuilder();
//		sb.append(n + " ");
//		for (int i = 0; i < n; i++) {
//			sb.append((i % 2 == 0 ? i/2+1 : i/2+n/2+1) + " ");
//		}
//		INPUT = sb.toString();


		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new FastWriter(System.out);

		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
		//		Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
		//			@Override
		//			public void run() {
		//				long s = System.currentTimeMillis();
		//				solve();
		//				out.flush();
		//				if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
		//			}
		//		};
		//		t.start();
		//		t.join();
	}

	private boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;

		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}

	private final 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 boolean isSpaceChar(int c) { return !(c >= 32 && 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))){
			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 long[] nal(int n)
	{
		long[] a = new long[n];
		for(int i = 0;i < n;i++)a[i] = nl();
		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();
		}
	}

	public static class FastWriter
	{
		private static final int BUF_SIZE = 1<<13;
		private final byte[] buf = new byte[BUF_SIZE];
		private final OutputStream out;
		private int ptr = 0;

		private FastWriter(){out = null;}

		public FastWriter(OutputStream os)
		{
			this.out = os;
		}

		public FastWriter(String path)
		{
			try {
				this.out = new FileOutputStream(path);
			} catch (FileNotFoundException e) {
				throw new RuntimeException("FastWriter");
			}
		}

		public FastWriter write(byte b)
		{
			buf[ptr++] = b;
			if(ptr == BUF_SIZE)innerflush();
			return this;
		}

		public FastWriter write(char c)
		{
			return write((byte)c);
		}

		public FastWriter write(char[] s)
		{
			for(char c : s){
				buf[ptr++] = (byte)c;
				if(ptr == BUF_SIZE)innerflush();
			}
			return this;
		}

		public FastWriter write(String s)
		{
			s.chars().forEach(c -> {
				buf[ptr++] = (byte)c;
				if(ptr == BUF_SIZE)innerflush();
			});
			return this;
		}

		private static int countDigits(int l) {
			if (l >= 1000000000) return 10;
			if (l >= 100000000) return 9;
			if (l >= 10000000) return 8;
			if (l >= 1000000) return 7;
			if (l >= 100000) return 6;
			if (l >= 10000) return 5;
			if (l >= 1000) return 4;
			if (l >= 100) return 3;
			if (l >= 10) return 2;
			return 1;
		}

		public FastWriter write(int x)
		{
			if(x == Integer.MIN_VALUE){
				return write((long)x);
			}
			if(ptr + 12 >= BUF_SIZE)innerflush();
			if(x < 0){
				write((byte)'-');
				x = -x;
			}
			int d = countDigits(x);
			for(int i = ptr + d - 1;i >= ptr;i--){
				buf[i] = (byte)('0'+x%10);
				x /= 10;
			}
			ptr += d;
			return this;
		}

		private static int countDigits(long l) {
			if (l >= 1000000000000000000L) return 19;
			if (l >= 100000000000000000L) return 18;
			if (l >= 10000000000000000L) return 17;
			if (l >= 1000000000000000L) return 16;
			if (l >= 100000000000000L) return 15;
			if (l >= 10000000000000L) return 14;
			if (l >= 1000000000000L) return 13;
			if (l >= 100000000000L) return 12;
			if (l >= 10000000000L) return 11;
			if (l >= 1000000000L) return 10;
			if (l >= 100000000L) return 9;
			if (l >= 10000000L) return 8;
			if (l >= 1000000L) return 7;
			if (l >= 100000L) return 6;
			if (l >= 10000L) return 5;
			if (l >= 1000L) return 4;
			if (l >= 100L) return 3;
			if (l >= 10L) return 2;
			return 1;
		}

		public FastWriter write(long x)
		{
			if(x == Long.MIN_VALUE){
				return write("" + x);
			}
			if(ptr + 21 >= BUF_SIZE)innerflush();
			if(x < 0){
				write((byte)'-');
				x = -x;
			}
			int d = countDigits(x);
			for(int i = ptr + d - 1;i >= ptr;i--){
				buf[i] = (byte)('0'+x%10);
				x /= 10;
			}
			ptr += d;
			return this;
		}

		public FastWriter write(double x, int precision)
		{
			if(x < 0){
				write('-');
				x = -x;
			}
			x += Math.pow(10, -precision)/2;
			//		if(x < 0){ x = 0; }
			write((long)x).write(".");
			x -= (long)x;
			for(int i = 0;i < precision;i++){
				x *= 10;
				write((char)('0'+(int)x));
				x -= (int)x;
			}
			return this;
		}

		public FastWriter writeln(char c){
			return write(c).writeln();
		}

		public FastWriter writeln(int x){
			return write(x).writeln();
		}

		public FastWriter writeln(long x){
			return write(x).writeln();
		}

		public FastWriter writeln(double x, int precision){
			return write(x, precision).writeln();
		}

		public FastWriter write(int... xs)
		{
			boolean first = true;
			for(int x : xs) {
				if (!first) write(' ');
				first = false;
				write(x);
			}
			return this;
		}

		public FastWriter write(long... xs)
		{
			boolean first = true;
			for(long x : xs) {
				if (!first) write(' ');
				first = false;
				write(x);
			}
			return this;
		}

		public FastWriter writeln()
		{
			return write((byte)'\n');
		}

		public FastWriter writeln(int... xs)
		{
			return write(xs).writeln();
		}

		public FastWriter writeln(long... xs)
		{
			return write(xs).writeln();
		}

		public FastWriter writeln(char[] line)
		{
			return write(line).writeln();
		}

		public FastWriter writeln(char[]... map)
		{
			for(char[] line : map)write(line).writeln();
			return this;
		}

		public FastWriter writeln(String s)
		{
			return write(s).writeln();
		}

		private void innerflush()
		{
			try {
				out.write(buf, 0, ptr);
				ptr = 0;
			} catch (IOException e) {
				throw new RuntimeException("innerflush");
			}
		}

		public void flush()
		{
			innerflush();
			try {
				out.flush();
			} catch (IOException e) {
				throw new RuntimeException("flush");
			}
		}

		public FastWriter print(byte b) { return write(b); }
		public FastWriter print(char c) { return write(c); }
		public FastWriter print(char[] s) { return write(s); }
		public FastWriter print(String s) { return write(s); }
		public FastWriter print(int x) { return write(x); }
		public FastWriter print(long x) { return write(x); }
		public FastWriter print(double x, int precision) { return write(x, precision); }
		public FastWriter println(char c){ return writeln(c); }
		public FastWriter println(int x){ return writeln(x); }
		public FastWriter println(long x){ return writeln(x); }
		public FastWriter println(double x, int precision){ return writeln(x, precision); }
		public FastWriter print(int... xs) { return write(xs); }
		public FastWriter print(long... xs) { return write(xs); }
		public FastWriter println(int... xs) { return writeln(xs); }
		public FastWriter println(long... xs) { return writeln(xs); }
		public FastWriter println(char[] line) { return writeln(line); }
		public FastWriter println(char[]... map) { return writeln(map); }
		public FastWriter println(String s) { return writeln(s); }
		public FastWriter println() { return writeln(); }
	}

	public static void trnz(int... o)
	{
		for(int i = 0;i < o.length;i++)if(o[i] != 0)System.out.print(i+":"+o[i]+" ");
		System.out.println();
	}

	// print ids which are 1
	public static void trt(long... o)
	{
		Queue<Integer> stands = new ArrayDeque<>();
		for(int i = 0;i < o.length;i++){
			for(long x = o[i];x != 0;x &= x-1)stands.add(i<<6|Long.numberOfTrailingZeros(x));
		}
		System.out.println(stands);
	}

	public static void tf(boolean... r)
	{
		for(boolean x : r)System.out.print(x?'#':'.');
		System.out.println();
	}

	public static void tf(boolean[]... b)
	{
		for(boolean[] r : b) {
			for(boolean x : r)System.out.print(x?'#':'.');
			System.out.println();
		}
		System.out.println();
	}

	public void tf(long[]... b)
	{
		if(INPUT.length() != 0) {
			for (long[] r : b) {
				for (long x : r) {
					for (int i = 0; i < 64; i++) {
						System.out.print(x << ~i < 0 ? '#' : '.');
					}
				}
				System.out.println();
			}
			System.out.println();
		}
	}

	public void tf(long... b)
	{
		if(INPUT.length() != 0) {
			for (long x : b) {
				for (int i = 0; i < 64; i++) {
					System.out.print(x << ~i < 0 ? '#' : '.');
				}
			}
			System.out.println();
		}
	}

	private void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}