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].


import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.util.Arrays;

public class CF1156E {
    public static void main(String[] args) throws Exception {
        boolean local = System.getProperty("ONLINE_JUDGE") == null;
        boolean async = false;

        Charset charset = Charset.forName("ascii");

        FastIO io = local ? new FastIO(new FileInputStream("D:\\DATABASE\\TESTCASE\\Code.in"), System.out, charset) : new FastIO(System.in, System.out, charset);
        Task task = new Task(io, new Debug(local));

        if (async) {
            Thread t = new Thread(null, task, "dalt", 1 << 27);
            t.setPriority(Thread.MAX_PRIORITY);
            t.start();
            t.join();
        } else {
            task.run();
        }

        if (local) {
            io.cache.append("\n\n--memory -- \n" + ((Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory()) >> 20) + "M");
        }

        io.flush();
    }

    public static class Task implements Runnable {
        final FastIO io;
        final Debug debug;
        int inf = (int) 1e8;
        int mod = (int) 1e9 + 7;

        public int mod(int val) {
            val %= mod;
            if (val < 0) {
                val += mod;
            }
            return val;
        }

        public int mod(long val) {
            val %= mod;
            if (val < 0) {
                val += mod;
            }
            return (int) val;
        }

        public Task(FastIO io, Debug debug) {
            this.io = io;
            this.debug = debug;
        }

        @Override
        public void run() {
            solve();
        }

        Segment s;
        int[] reverse;
        int[] data;
        int n;
        VersionArray array;

        public void solve() {
            n = io.readInt();
            data = new int[n + 1];
            reverse = new int[n + 1];
            for (int i = 1; i <= n; i++) {
                data[i] = io.readInt();
                reverse[data[i]] = i;
            }
            s = Segment.build(1, n, data);
            array = new VersionArray(n + 1);
            Node root = buildTree(1, n);
            dsu(root);
            io.cache.append(root.total);
        }

        public void contribute(Node node, int target) {
            if (node == Node.NIL) {
                return;
            }
            if (array.get(target - node.val) == 1) {
                array.inc(0);
            }
            contribute(node.left, target);
            contribute(node.right, target);
        }

        public void record(Node node) {
            if (node == Node.NIL) {
                return;
            }
            array.set(node.val, 1);
            record(node.left);
            record(node.right);
        }

        public void dsu(Node node) {
            if (node == Node.NIL) {
                return;
            }
            Node light = node.left != node.heavy ? node.left : node.right;
            dsu(light);
            array.clear();
            dsu(node.heavy);
            array.set(0, 0);
            contribute(light, node.val);
            record(light);
            node.cnt = array.get(0);
            node.total = node.cnt + node.left.total + node.right.total;
            array.set(node.val, 1);
        }

        public Node buildTree(int l, int r) {
            if (l > r) {
                return Node.NIL;
            }
            int maxValue = Segment.query(l, r, 1, n, s);
            int index = reverse[maxValue];
            Node node = new Node();
            node.val = maxValue;
            node.left = buildTree(l, index - 1);
            node.right = buildTree(index + 1, r);
            node.size = node.left.size + node.right.size + 1;
            node.heavy = node.left.size > node.right.size ? node.left : node.right;
            return node;
        }
    }

    public static class Node {
        static final Node NIL = new Node();
        Node left;
        Node right;
        int size;
        int val;
        Node heavy;
        int cnt;
        long total;

        @Override
        public String toString() {
            if(this == NIL)
            {
                return "";
            }
            return left  + "" + val + " " + right;
        }
    }

    public static class VersionArray {
        int[] data;
        int[] version;
        int now;

        public VersionArray(int cap) {
            data = new int[cap];
            version = new int[cap];
            now = 0;
        }

        public void clear() {
            now++;
        }

        public void visit(int i) {
            if (version[i] < now) {
                version[i] = now;
                data[i] = 0;
            }
        }

        public void set(int i, int v) {
            version[i] = now;
            data[i] = v;
        }

        public int get(int i) {
            visit(i);
            return data[i];
        }

        public int inc(int i) {
            visit(i);
            return ++data[i];
        }
    }

    public static class Segment implements Cloneable {
        Segment left;
        Segment right;
        int max;

        public static Segment build(int l, int r, int[] data) {
            Segment segment = new Segment();
            if (l != r) {
                int m = (l + r) >> 1;
                segment.left = build(l, m, data);
                segment.right = build(m + 1, r, data);
                segment.pushUp();
            } else {
                segment.max = data[l];
            }
            return segment;
        }

        public static boolean checkOutOfRange(int ll, int rr, int l, int r) {
            return ll > r || rr < l;
        }

        public static boolean checkCoverage(int ll, int rr, int l, int r) {
            return ll <= l && rr >= r;
        }

        public static void update(int ll, int rr, int l, int r, Segment segment) {
            if (checkOutOfRange(ll, rr, l, r)) {
                return;
            }
            if (checkCoverage(ll, rr, l, r)) {
                return;
            }
            int m = (l + r) >> 1;

            segment.pushDown();
            update(ll, rr, l, m, segment.left);
            update(ll, rr, m + 1, r, segment.right);
            segment.pushUp();
        }

        public static Segment updatePersistently(int ll, int rr, int l, int r, Segment segment) {
            if (checkOutOfRange(ll, rr, l, r)) {
                return segment;
            }
            segment = segment.clone();
            if (checkCoverage(ll, rr, l, r)) {
                return segment;
            }

            int m = (l + r) >> 1;

            segment.pushDown();
            segment.left = updatePersistently(ll, rr, l, m, segment.left);
            segment.right = updatePersistently(ll, rr, m + 1, r, segment.right);
            segment.pushUp();
            return segment;
        }

        public static int query(int ll, int rr, int l, int r, Segment segment) {
            if (checkOutOfRange(ll, rr, l, r)) {
                return 0;
            }
            if (checkCoverage(ll, rr, l, r)) {
                return segment.max;
            }
            int m = (l + r) >> 1;

            segment.pushDown();
            return Math.max(query(ll, rr, l, m, segment.left),
                    query(ll, rr, m + 1, r, segment.right));
        }

        public void pushDown() {
        }

        public void pushUp() {
            max = Math.max(left.max, right.max);
        }

        @Override
        public Segment clone() {
            try {
                return (Segment) super.clone();
            } catch (CloneNotSupportedException e) {
                throw new RuntimeException(e);
            }
        }
    }

    public static class FastIO {
        public final StringBuilder cache = new StringBuilder();
        private final InputStream is;
        private final OutputStream os;
        private final Charset charset;
        private StringBuilder defaultStringBuf = new StringBuilder(1 << 8);
        private byte[] buf = new byte[1 << 13];
        private int bufLen;
        private int bufOffset;
        private int next;

        public FastIO(InputStream is, OutputStream os, Charset charset) {
            this.is = is;
            this.os = os;
            this.charset = charset;
        }

        public FastIO(InputStream is, OutputStream os) {
            this(is, os, Charset.forName("ascii"));
        }

        private int read() {
            while (bufLen == bufOffset) {
                bufOffset = 0;
                try {
                    bufLen = is.read(buf);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
                if (bufLen == -1) {
                    return -1;
                }
            }
            return buf[bufOffset++];
        }

        public void skipBlank() {
            while (next >= 0 && next <= 32) {
                next = read();
            }
        }

        public int readInt() {
            int sign = 1;

            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+' ? 1 : -1;
                next = read();
            }

            int val = 0;
            if (sign == 1) {
                while (next >= '0' && next <= '9') {
                    val = val * 10 + next - '0';
                    next = read();
                }
            } else {
                while (next >= '0' && next <= '9') {
                    val = val * 10 - next + '0';
                    next = read();
                }
            }

            return val;
        }

        public long readLong() {
            int sign = 1;

            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+' ? 1 : -1;
                next = read();
            }

            long val = 0;
            if (sign == 1) {
                while (next >= '0' && next <= '9') {
                    val = val * 10 + next - '0';
                    next = read();
                }
            } else {
                while (next >= '0' && next <= '9') {
                    val = val * 10 - next + '0';
                    next = read();
                }
            }

            return val;
        }

        public double readDouble() {
            boolean sign = true;
            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+';
                next = read();
            }

            long val = 0;
            while (next >= '0' && next <= '9') {
                val = val * 10 + next - '0';
                next = read();
            }
            if (next != '.') {
                return sign ? val : -val;
            }
            next = read();
            long radix = 1;
            long point = 0;
            while (next >= '0' && next <= '9') {
                point = point * 10 + next - '0';
                radix = radix * 10;
                next = read();
            }
            double result = val + (double) point / radix;
            return sign ? result : -result;
        }

        public String readString(StringBuilder builder) {
            skipBlank();

            while (next > 32) {
                builder.append((char) next);
                next = read();
            }

            return builder.toString();
        }

        public String readString() {
            defaultStringBuf.setLength(0);
            return readString(defaultStringBuf);
        }

        public int readLine(char[] data, int offset) {
            int originalOffset = offset;
            while (next != -1 && next != '\n') {
                data[offset++] = (char) next;
                next = read();
            }
            return offset - originalOffset;
        }

        public int readString(char[] data, int offset) {
            skipBlank();

            int originalOffset = offset;
            while (next > 32) {
                data[offset++] = (char) next;
                next = read();
            }

            return offset - originalOffset;
        }

        public int readString(byte[] data, int offset) {
            skipBlank();

            int originalOffset = offset;
            while (next > 32) {
                data[offset++] = (byte) next;
                next = read();
            }

            return offset - originalOffset;
        }

        public char readChar() {
            skipBlank();
            char c = (char) next;
            next = read();
            return c;
        }

        public void flush() {
            try {
                os.write(cache.toString().getBytes(charset));
                os.flush();
                cache.setLength(0);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }

        public boolean hasMore() {
            skipBlank();
            return next != -1;
        }
    }

    public static class Debug {
        private boolean allowDebug;

        public Debug(boolean allowDebug) {
            this.allowDebug = allowDebug;
        }

        public void assertTrue(boolean flag) {
            if (!allowDebug) {
                return;
            }
            if (!flag) {
                fail();
            }
        }

        public void fail() {
            throw new RuntimeException();
        }

        public void assertFalse(boolean flag) {
            if (!allowDebug) {
                return;
            }
            if (flag) {
                fail();
            }
        }

        private void outputName(String name) {
            System.out.print(name + " = ");
        }

        public void debug(String name, int x) {
            if (!allowDebug) {
                return;
            }

            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, long x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, double x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, int[] x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.toString(x));
        }

        public void debug(String name, long[] x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.toString(x));
        }

        public void debug(String name, double[] x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.toString(x));
        }

        public void debug(String name, Object x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println("" + x);
        }

        public void debug(String name, Object... x) {
            if (!allowDebug) {
                return;
            }
            outputName(name);
            System.out.println(Arrays.deepToString(x));
        }
    }
}
