import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.util.ArrayList; import java.util.HashMap; import java.util.List; public class Main { public static void main(String[] args) throws NumberFormatException, IOException {Solve solve = new Solve();solve.solve();} } class Solve{ void dump(int[]a){for(int i=0;i list = new ArrayList<>(); int[] b = new int[n]; for(int i=0; ii; j--){ list.add((j)+" "+(j+1)); map[a[j]]--; map[a[j-1]]++; int tmp = a[j-1]; a[j-1] = a[j]; a[j] = tmp; } } System.out.println(list.size()); for(String s: list) System.out.println(s); } } class MultiSet extends HashMap{ @Override public Integer get(Object key){return containsKey(key)?super.get(key):0;} public void add(T key,int v){put(key,get(key)+v);} public void add(T key){put(key,get(key)+1);} public void sub(T key){ final int num = get(key); if(num==1) remove(key); else put(key, num-1); } } class Timer{ long time; public void set(){time = System.currentTimeMillis();} public long stop(){return System.currentTimeMillis()-time;} } class Writer extends PrintWriter{ public Writer(String filename) throws IOException {super(new BufferedWriter(new FileWriter(filename)));} public Writer() throws IOException{super(System.out);} } class ContestScanner { private BufferedReader reader; private String[] line; private int idx; public ContestScanner() throws FileNotFoundException {reader = new BufferedReader(new InputStreamReader(System.in));} public ContestScanner(String filename) throws FileNotFoundException {reader = new BufferedReader(new InputStreamReader(new FileInputStream(filename)));} public String nextToken() throws IOException { if (line == null || line.length <= idx) { line = reader.readLine().trim().split(" "); idx = 0; } return line[idx++]; } public String readLine() throws IOException{return reader.readLine();} public long nextLong() throws IOException, NumberFormatException {return Long.parseLong(nextToken());} public int nextInt() throws NumberFormatException, IOException {return (int) nextLong();} public double nextDouble() throws NumberFormatException, IOException {return Double.parseDouble(nextToken());} }