Let's arrange a deck of cards. Your task is to sort totally n cards. A card consists of a part of a suit (S, H, C or D) and an number. Write a program which sorts such cards based on the following pseudocode:


Partition(A, p, r)
1 x = A[r]
2 i = p-1
3 for j = p to r-1
4     do if A[j] <= x
5        then i = i+1
6            exchange A[i] and A[j]
7 exchange A[i+1] and A[r]
8 return i+1


Quicksort(A, p, r)
1 if p < r
2    then q = Partition(A, p, r)
3        run Quicksort(A, p, q-1)
4        run Quicksort(A, q+1, r)


Here, A is an array which represents a deck of cards and comparison operations are performed based on the numbers.

Your program should also report the stability of the output for the given input (instance). Here, 'stability of the output' means that: cards with the same value appear in the output in the same order as they do in the input (instance).

Constraints

* 1 ≤ n ≤ 100,000
* 1 ≤ the number of a card ≤ 109
* There are no identical card in the input

Input

The first line contains an integer n, the number of cards.

n cards are given in the following lines. Each card is given in a line and represented by a pair of a character and an integer separated by a single space.

Output

In the first line, print the stability ("Stable" or "Not stable") of this output.

In the following lines, print the arranged cards in the same manner of that of the input.

Examples

Input

6
D 3
H 2
D 1
S 3
D 2
C 1


Output

Not stable
D 1
C 1
D 2
H 2
D 3
S 3


Input

2
S 1
H 1


Output

Stable
S 1
H 1
import java.io.*;
import java.util.*;

public class Main {

    private static final int MAX = 100000;
    private static final int SENTINEL = 2000000000; // 番兵
    private static Card[] L = new Card[MAX/2+2];
    private static Card[] R = new Card[MAX/2+2];

    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        int n = sc.nextInt();
        Card[] A = new Card[n];
        Card[] B = new Card[n];
        boolean stable = true;
        for(int i=0; i<n; i++){
            A[i] = B[i] = new Card(sc.next().charAt(0), sc.nextInt());
        }

        mergeSort(A, n, 0, n);
        quickSort(B, n, 0, n-1);
        for(int i=0; i<n; i++){
            if(A[i].suit != B[i].suit) stable = false;
        }

        if(stable) out.println("Stable");
        else out.println("Not stable");
        for(int i=0; i<n; i++){
            out.printf("%s %d\n", B[i].suit, B[i].value);
        }
        out.flush();
    }
    static class Card{
        private char suit = 'A';
        private int value = 0;

        public Card(char suit, int value){
            this.suit = suit;
            this.value = value;
        }

        public String toString(){
            return this.suit + " " + this.value;
        }
    }

    static void merge(Card A[],int n, int left, int mid, int right){
        int n1 = mid - left;
        int n2 = right - mid;
        for (int i=0; i<n1; i++) L[i] = A[left + i];
        for(int i=0; i<n2; i++) R[i] = A[mid + i];
        L[n1] = R[n2] = new Card('A', SENTINEL);
        // L[n1].value = R[n2].value = SENTINEL;
        int i = 0;
        int j = 0;
        for(int k=left; k<right; k++){
            // 比較回数を計算
            // 小さい方を元の配列に格納する
            if(L[i].value <= R[j].value){
                A[k] = L[i++];
            }else{
                A[k] = R[j++];
            }
        }
    }
    static void mergeSort(Card A[], int n, int left, int right){
        // left と right の　差が 1 より上だったら
        if(left+1 < right){
            int mid = (left + right)/2;
            mergeSort(A, n, left ,mid);
            mergeSort(A, n, mid, right);
            merge(A, n, left, mid, right);
        }
    }

    static void quickSort(Card A[], int n, int p, int r){
        int q;
        if(p < r){
            q = partition(A, n, p, r);
            quickSort(A,n,p,q-1);
            quickSort(A,n,q+1,r);
        }
    }


    static int partition(Card A[], int n, int p, int r){
        Card x = A[r];
        int i = p - 1;
        Card t;
        for(int j=p; j<r; j++){
            if (A[j].value <= x.value) {
                i++;
                // swap
                t = A[i];
                A[i] = A[j];
                A[j] = t;
            }
            // 大きかったらjを1進めるだけで良い
        }
        // swap
        t = A[i+1];
        A[i+1] = A[r];
        A[r] = t;
        return i+1;
    }

    static class FastScanner {
        private BufferedReader reader = null;
        private StringTokenizer tokenizer = null;

        public FastScanner(InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
            tokenizer = null;
        }

        public String next() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public String nextLine() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    return reader.readLine();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }

            return tokenizer.nextToken("\n");
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }
}
