Problem: Graph constructive problems are back! This time the graph you are asked to build should match the following properties.

The graph is connected if and only if there exists a path between every pair of vertices.

The diameter (aka "longest shortest path") of a connected undirected graph is the maximum number of edges in the shortest path between any pair of its vertices.

The degree of a vertex is the number of edges incident to it.

Given a sequence of n integers a_1, a_2, ..., a_n construct a connected undirected graph of n vertices such that:

  * the graph contains no self-loops and no multiple edges; 
  * the degree d_i of the i-th vertex doesn't exceed a_i (i.e. d_i ≤ a_i); 
  * the diameter of the graph is maximum possible. 



Output the resulting graph or report that no solution exists.

Input

The first line contains a single integer n (3 ≤ n ≤ 500) — the number of vertices in the graph.

The second line contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ n - 1) — the upper limits to vertex degrees.

Output

Print "NO" if no graph can be constructed under the given conditions.

Otherwise print "YES" and the diameter of the resulting graph in the first line.

The second line should contain a single integer m — the number of edges in the resulting graph.

The i-th of the next m lines should contain two integers v_i, u_i (1 ≤ v_i, u_i ≤ n, v_i ≠ u_i) — the description of the i-th edge. The graph should contain no multiple edges — for each pair (x, y) you output, you should output no more pairs (x, y) or (y, x).

Examples

Input


3
2 2 2


Output


YES 2
2
1 2
2 3


Input


5
1 4 1 1 1


Output


YES 2
4
1 2
3 2
4 2
5 2


Input


3
1 1 1


Output


NO

Note

Here are the graphs for the first two example cases. Both have diameter of 2.

<image> d_1 = 1 ≤ a_1 = 2

d_2 = 2 ≤ a_2 = 2

d_3 = 1 ≤ a_3 = 2 

<image> d_1 = 1 ≤ a_1 = 1

d_2 = 4 ≤ a_2 = 4

d_3 = 1 ≤ a_3 = 1

d_4 = 1 ≤ a_4 = 1 

Solution (in JAVA):

Solution:
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.InputMismatchException;
import java.util.Set;
import java.util.TreeMap;

public class D {
	public static ArrayList<Integer> sieve = sieveOfEratosthenes(100000);
	public static int ans1 = 0;
	public static int perfect = 0;

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		InputReader s = new InputReader(System.in);
		PrintWriter p = new PrintWriter(System.out);
		ArrayList<Integer> test = new ArrayList<>();
		int n = s.nextInt();
		ArrayList<Edge> list = new ArrayList<>();
		int n1 = 0;
		int nrest = 0;
		int remdeg = 0;
		for (int i = 0; i < n; i++) {
			int curr = s.nextInt();
			Edge edge = new Edge(i + 1, curr);
			list.add(edge);
			if (curr == 1) {
				n1++;
			} else {
				nrest++;
				remdeg += curr;
			}
		}

		int nedge = nrest - 1;
		remdeg -= (2*nedge);
		Collections.sort(list);
		if (remdeg < n1) {
			p.print("NO");
			p.flush();
			p.close();
			return;
		}
		p.print("YES ");
		n1 = Math.min(2, n1);
		p.println(nedge + n1);
		p.println(n-1);
		for (int i = 0; i < nrest - 1; i++) {
			Edge curr = list.get(i);
			Edge next = list.get(i + 1);
			p.println(curr.index + " " + next.index);
			curr.maxdeg--;
			next.maxdeg--;
			list.set(i, curr);
			list.set(i + 1, next);
		}
		if (n1 == 1) {
			Edge first = list.get(0);
			Edge last = list.get(list.size() - 1);
			p.println(first.index + " " + last.index);
		} else if(n1 > 1){
			Edge n11 = list.get(nrest);
			Edge n12 = list.get(nrest + 1);
			Edge first = list.get(0);
			Edge last = list.get(nrest - 1);
			p.println(first.index + " " + n11.index);
			p.println(last.index + " " + n12.index);
			first.maxdeg--;
			last.maxdeg--;
			list.set(0, first);
			list.set(nrest - 1, last);
		}
		int od = 0;
		int i = nrest + 2;
		while (i < list.size()) {
			Edge curr = list.get(od);
			Edge curr1 = list.get(i);
			if (curr.maxdeg > 0) {
				p.println(curr.index + " " + curr1.index);
				curr.maxdeg--;
				i++;
			} else {
				od++;
			}
		}
		p.flush();
		p.close();
	}

	public static class Edge implements Comparable<Edge>{
		int index, maxdeg;

		Edge(int i, int m) {
			this.index = i;
			this.maxdeg = m;
		}

		public int compareTo(Edge edge) {
			return edge.maxdeg - this.maxdeg;
		}
	}

	public static ArrayList<Integer> sieveOfEratosthenes(int n) {
		boolean prime[] = new boolean[n + 1];
		for (int i = 0; i < n; i++)
			prime[i] = true;

		for (int p = 2; p * p <= n; p++) {
			// If prime[p] is not changed, then it is a prime
			if (prime[p] == true) {
				// Update all multiples of p
				for (int i = p * p; i <= n; i += p)
					prime[i] = false;
			}
		}
		ArrayList<Integer> ans = new ArrayList<>();
		// Print all prime numbers
		for (int i = 2; i <= n; i++) {
			if (prime[i] == true)
				ans.add(i);
		}
		return ans;
	}

	public static int BinarySearch(long[] a, long k) {
		int n = a.length;
		int i = 0, j = n - 1;
		int mid = 0;

		if (k < a[0])
			return 0;
		else if (k >= a[n - 1])
			return n;
		else {
			while (j - i > 1) {
				mid = (i + j) / 2;

				if (k >= a[mid])
					i = mid;
				else
					j = mid;
			}
		}

		return i + 1;
	}

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

	public static long LCM(long a, long b) {
		return (a * b) / GCD(a, b);
	}

	static class pair implements Comparable<pair> {
		Integer x, y;

		pair(int x, int y) {
			this.x = x;
			this.y = y;
		}

		public int compareTo(pair o) {
			int result = x.compareTo(o.x);
			if (result == 0)
				result = y.compareTo(o.y);

			return result;
		}

		public String toString() {
			return x + " " + y;
		}

		public boolean equals(Object o) {
			if (o instanceof pair) {
				pair p = (pair) o;
				return p.x - x == 0 && p.y - y == 0;
			}
			return false;
		}

		public int hashCode() {
			return new Long(x).hashCode() * 31 + new Long(y).hashCode();
		}
	}

	static class InputReader {

		private final InputStream stream;
		private final byte[] buf = new byte[8192];
		private int curChar, snumChars;
		private SpaceCharFilter filter;

		public InputReader(InputStream stream) {
			this.stream = stream;
		}

		public int snext() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public int nextInt() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public long nextLong() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

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

		public String readString() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public String nextLine() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public boolean isSpaceChar(int c) {
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}
	}

	static class CodeX {
		public static void sort(long arr[]) {
			merge_sort(arr, 0, arr.length - 1);
		}

		private static void merge_sort(long A[], long start, long end) {
			if (start < end) {
				long mid = (start + end) / 2;
				merge_sort(A, start, mid);
				merge_sort(A, mid + 1, end);
				merge(A, start, mid, end);
			}

		}

		public static long power(long x, long y, long p) {

			long res = 1;

			// Update x if it is more
			// than or equal to p
			x = x % p;

			while (y > 0) {
				// If y is odd, multiply x
				// with result
				if ((y & 1) == 1)
					res = (res * x) % p;

				// y must be even now
				// y = y / 2
				y = y >> 1;
				x = (x * x) % p;
			}
			return res;
		}

		private static void merge(long A[], long start, long mid, long end) {
			long p = start, q = mid + 1;
			long Arr[] = new long[(int) (end - start + 1)];
			long k = 0;

			for (int i = (int) start; i <= end; i++) {
				if (p > mid)
					Arr[(int) k++] = A[(int) q++];

				else if (q > end)
					Arr[(int) k++] = A[(int) p++];

				else if (A[(int) p] < A[(int) q])
					Arr[(int) k++] = A[(int) p++];

				else
					Arr[(int) k++] = A[(int) q++];
			}
			for (int i = 0; i < k; i++) {
				A[(int) start++] = Arr[i];
			}

		}

	}

}