#include <bits/stdc++.h>   using namespace std;   int n, a[100001], g[100001], h[100001], m;   set<int> events[100001];   int main() {     scanf( %d , &n);     for (int i = 1; i <= n; i++) events[i].clear();     for (int i = 1; i <= n; i++) scanf( %d , &a[i]), events[a[i]].insert(i);     m = 0;     bool ok = true;     for (int i = 1; i <= n; ++i)       if (!events[i].empty())         if (events[i].find(i) == events[i].end()) {           ok = false;           break;         }     if (!ok) {       printf( -1 n );       return 0;     }     for (int i = 1; i <= n; i++)       if (!events[i].empty()) {         h[++m] = i;         for (set<int>::iterator itr = events[i].begin(); itr != events[i].end();              ++itr)           g[*itr] = m;       }     printf( %d n , m);     for (int i = 1; i <= n; i++) printf( %d  , g[i]);     printf(  n );     for (int i = 1; i <= m; i++) printf( %d  , h[i]);     printf(  n );   }   