#include <bits/stdc++.h>
using namespace std;
const long long INFll = 0x3f3f3f3f3f3f3f3fll;
int n, m = 0;
int f[100005];
int g[100005];
int h[100005];
int main() {
  memset(f, 0, sizeof(f));
  memset(g, 0, sizeof(g));
  memset(h, 0, sizeof(h));
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &f[i]);
  }
  for (int i = 1; i <= n; i++) {
    if (f[f[i]] != f[i]) {
      printf("-1\n");
      return 0;
    }
    if (f[i] == i) {
      h[++m] = i;
    }
  }
  for (int i = 1; i <= m; i++) {
    g[h[i]] = i;
  }
  for (int i = 1; i <= n; i++) {
    if (g[i]) g[f[i]] = g[i];
    if (g[f[i]]) g[i] = g[f[i]];
  }
  printf("%d\n", m);
  for (int i = 1; i <= n - 1; i++) {
    printf("%d ", g[i]);
  }
  printf("%d\n", g[n]);
  for (int i = 1; i <= m - 1; i++) {
    printf("%d ", h[i]);
  }
  printf("%d\n", h[m]);
  return 0;
}
