3
2 1 1
 6
6 2 6 2 4 2
 2
1 2
 8
2 1 2 2 6 5 6 6
 18
2 3 4 5 2 7 8 9 10 7 11 12 14 15 13 17 18 18
 7
1 2 3 4 5 6 7
 7
4 3 2 6 3 5 2
 7
7 5 3 1 2 1 5
 7
1 6 4 4 5 6 7

1
2 2 1  0
6 2 6 2 4 2  1 
1 1 
 2 
2 2 2 2 6 2 6 6 
 5 
2 3 4 5 11 7 8 9 10 11 11 11 14 15 11 17 18 11 
 6 
1 1 1 1 1 1 1 
 1
4 3 3 6 3 5 2  1
7 5 3 1 3 1 5  4 
1 6 4 1 1 1 1 


import java.io.*;
import java.util.*;

public class Main {

	static long sx = 0, sy = 0, m = (long) (1e9 + 7);

	static ArrayList<Integer>[] a;
	static int[][] dp;
	static long[] farr;
	// static boolean b = true;
	static HashMap<Integer, Integer> hm = new HashMap<>();

	// static TreeMap<Integer, Integer> hm = new TreeMap<>();
	public static PrintWriter out;
	static ArrayList<pair> p = new ArrayList<>();
	static long[] fact = new long[(int) 1e6];
	static boolean b = false;
	static StringBuilder sb = new StringBuilder();
	static boolean cycle = false;
	static long mod = 998244353;
	static int[] col;
	// static HashSet<Integer> p = new HashSet<>();
	static int cnt;

	public static void main(String[] args) throws IOException {

		// Scanner scn = new Scanner(System.in);

		Reader scn = new Reader();
		out = new PrintWriter(System.out);

		int n = scn.nextInt();
		int[] a = new int[n + 1];

		for (int i = 1; i <= n; i++)
			a[i] = scn.nextInt();

		dsu d = new dsu(n);

		TreeSet<Integer> hm = new TreeSet<>();

		for (int i = 1; i <= n; i++) {

			if (!d.merge(i, a[i])) {
				a[i] = -1;
				hm.add(i);
			}
		}

		for (int i = 1; i <= n; i++) {

			if (a[i] == -1) {

				if (hm.higher(i) != null)
					a[i] = hm.higher(i);
				else
					a[i] = i;
			}
		}

		System.out.println(hm.size()-1);
		for (int i = 1; i <= n; i++)
			System.out.print(a[i] + " ");

	}

	private static class dsu {

		static int[] size;
		static int[] par;

		dsu(int n) {

			size = new int[n + 1];
			par = new int[n + 1];

			for (int i = 1; i <= n; i++) {
				size[i] = 1;
				par[i] = i;
			}
		}

		public static boolean merge(int u, int v) {

			int p1 = find(u);

			int p2 = find(v);

			if (p1 == p2)
				return false;

			if (size[p1] >= size[p2]) {
				size[p1] += size[p2];
				par[p2] = p1;
			}

			else {
				size[p2] += size[p1];
				par[p1] = par[p2];
			}

			return true;
		}

		public static int find(int v) {

			if (v == par[v])
				return v;

			par[v] = find(par[v]);

			return par[v];
		}
	}

	// _________________________TEMPLATE_____________________________________________________________

	// private static int gcd(int a, int b) {
	// if (a == 0)
	// return b;
	//
	// return gcd(b % a, a);
	// }

	// static class comp implements Comparator<Integer> {
	//
	// @Override
	// public int compare(Integer o1, Integer o2) {
	// if (b[o1])
	// return -1;
	// else if (b[o2])
	// return 1;
	// else
	// return (int) (a[o2].size() - a[o1].size());
	// }
	//
	// }

	// public static long pow(long a, long b) {
	//
	// if(b<0)return 0;
	// if (b == 0 || b == 1)
	// return (long) Math.pow(a, b);
	//
	// if (b % 2 == 0) {
	//
	// long ret = pow(a, b / 2);
	// ret = (ret % mod * ret % mod) % mod;
	// return ret;
	// }
	//
	// else {
	// return ((pow(a, b - 1) % mod) * a % mod) % mod;
	// }
	// }

	private static class pair implements Comparable<pair> {

		int tb, tbw;

		pair() {
			tb = tbw = 0;
		}

		@Override
		public int compareTo(pair o) {

			return 1;
		}

	}

	private static String reverse(String s) {

		return new StringBuilder(s).reverse().toString();
	}

	public static class Reader {
		final private int BUFFER_SIZE = 1 << 16;
		private DataInputStream din;
		private byte[] buffer;
		private int bufferPointer, bytesRead;

		public Reader() {
			din = new DataInputStream(System.in);
			buffer = new byte[BUFFER_SIZE];
			bufferPointer = bytesRead = 0;
		}

		public Reader(String file_name) throws IOException {
			din = new DataInputStream(new FileInputStream(file_name));
			buffer = new byte[BUFFER_SIZE];
			bufferPointer = bytesRead = 0;
		}

		public String readLine() throws IOException {
			byte[] buf = new byte[1000000 + 1]; // line length
			int cnt = 0, c;
			while ((c = read()) != -1) {
				if (c == '\n')
					break;
				buf[cnt++] = (byte) c;
			}
			return new String(buf, 0, cnt);
		}

		public int nextInt() throws IOException {
			int ret = 0;
			byte c = read();
			while (c <= ' ')
				c = read();
			boolean neg = (c == '-');
			if (neg)
				c = read();
			do {
				ret = ret * 10 + c - '0';
			} while ((c = read()) >= '0' && c <= '9');

			if (neg)
				return -ret;
			return ret;
		}

		public long nextLong() throws IOException {
			long ret = 0;
			byte c = read();
			while (c <= ' ')
				c = read();
			boolean neg = (c == '-');
			if (neg)
				c = read();
			do {
				ret = ret * 10 + c - '0';
			} while ((c = read()) >= '0' && c <= '9');
			if (neg)
				return -ret;
			return ret;
		}

		public double nextDouble() throws IOException {
			double ret = 0, div = 1;
			byte c = read();
			while (c <= ' ')
				c = read();
			boolean neg = (c == '-');
			if (neg)
				c = read();

			do {
				ret = ret * 10 + c - '0';
			} while ((c = read()) >= '0' && c <= '9');

			if (c == '.') {
				while ((c = read()) >= '0' && c <= '9') {
					ret += (c - '0') / (div *= 10);
				}
			}

			if (neg)
				return -ret;
			return ret;
		}

		private void fillBuffer() throws IOException {
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
			if (bytesRead == -1)
				buffer[0] = -1;
		}

		private byte read() throws IOException {
			if (bufferPointer == bytesRead)
				fillBuffer();
			return buffer[bufferPointer++];
		}

		public void close() throws IOException {
			if (din == null)
				return;
			din.close();
		}

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

		public long[] nextLongArray(int n) throws IOException {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public int[][] nextInt2DArray(int m, int n) throws IOException {
			int[][] arr = new int[m][n];
			for (int i = 0; i < m; i++) {
				for (int j = 0; j < n; j++)
					arr[i][j] = nextInt();
			}
			return arr;
		}
		// kickstart - Solution
		// atcoder - Main
	}

}
