package contest; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Arrays; import java.util.BitSet; import java.util.InputMismatchException; public class Q642 { InputStream is; PrintWriter out; String INPUT = ""; void solve() { int n = ni(); int[] a = na(n); boolean[][] g = new boolean[n][n]; for(int i = 0;i < n;i++){ Arrays.fill(g[i], true); } for(int i = 0;i < n;i++){ if(a[i] < n){ g[i][a[i]] = false; } } int[] mat = doBipartiteMatching(g); if(mat == null){ out.println(-1); }else{ for(int i = 0;i < n;i++){ out.print(mat[i] + " "); } out.println(); } } public static int[] doBipartiteMatching(boolean[][] g) { int n = g.length; if(n == 0)return new int[0]; int m = g[0].length; if(m == 0)return new int[n]; int[] im = new int[m]; Arrays.fill(im, -1); BitSet visited = new BitSet(); int matched = 0; for(int i = 0;i < n;i++){ if(visit(g, i, visited, im)) { visited.clear(); matched++; } } int[] ret = new int[n]; Arrays.fill(ret, -1); for(int i = 0;i < m;i++){ if(im[i] != -1)ret[im[i]] = i; } if(matched != n)return null; return ret; } public static boolean visit(boolean[][] g, int cur, BitSet visited, int[] im) { if(cur == -1)return true; for(int i = visited.nextClearBit(0);i != g[cur].length;i = visited.nextClearBit(i+1)){ if(g[cur][i]){ visited.set(i); if(visit(g, im[i], visited, im)){ im[i] = cur; return true; } } } return false; } void run() throws Exception { is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes()); out = new PrintWriter(System.out); long s = System.currentTimeMillis(); solve(); out.flush(); if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms"); } public static void main(String[] args) throws Exception { new Q642().run(); } private byte[] inbuf = new byte[1024]; private int lenbuf = 0, ptrbuf = 0; private int readByte() { if(lenbuf == -1)throw new InputMismatchException(); if(ptrbuf >= lenbuf){ ptrbuf = 0; try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); } if(lenbuf <= 0)return -1; } return inbuf[ptrbuf++]; } private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); } private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; } private double nd() { return Double.parseDouble(ns()); } private char nc() { return (char)skip(); } private String ns() { int b = skip(); StringBuilder sb = new StringBuilder(); while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ') sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } private char[] ns(int n) { char[] buf = new char[n]; int b = skip(), p = 0; while(p < n && !(isSpaceChar(b))){ buf[p++] = (char)b; b = readByte(); } return n == p ? buf : Arrays.copyOf(buf, p); } private char[][] nm(int n, int m) { char[][] map = new char[n][]; for(int i = 0;i < n;i++)map[i] = ns(m); return map; } private int[] na(int n) { int[] a = new int[n]; for(int i = 0;i < n;i++)a[i] = ni(); return a; } private int ni() { int num = 0, b; boolean minus = false; while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')); if(b == '-'){ minus = true; b = readByte(); } while(true){ if(b >= '0' && b <= '9'){ num = num * 10 + (b - '0'); }else{ return minus ? -num : num; } b = readByte(); } } private long nl() { long num = 0; int b; boolean minus = false; while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')); if(b == '-'){ minus = true; b = readByte(); } while(true){ if(b >= '0' && b <= '9'){ num = num * 10 + (b - '0'); }else{ return minus ? -num : num; } b = readByte(); } } private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); } }