#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define bug(x) cout << #x << " : " << x << '\n'
#define ios ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0)
typedef long long ll;
typedef pair<int, int> pii;
const int maxn = 1e5 + 10;
const int mod = 1e9 + 7;
const int inf = 1e9 + 10;
int a[maxn], b[maxn], d[maxn];
int vis[maxn];
vector<int> G[maxn];
priority_queue<int, vector<int>, greater<int>> Q;
void dfs(int v){
vis[v] = 1;
for(int u : G[v]){
if(!vis[u])
dfs(u);
else if(vis[u] == 1){
cout << "-1\n";
exit(0);
}
}
vis[v] = 2;
}
int main(){
ios;
int n, k;
cin >> n >> k;
if(k > 1)
return 0;
for(int i = 1; i <= n; i ++){
cin >> b[i];
}
if(~b[n])
return cout << "-1\n", 0;
vector<pii> S;
for(int i = n; i; i --){
if(b[i] == -1){
if(!S.empty()){
G[S.front().fi].pb(i);
d[i] ++;
}
S.clear();
S.pb(mp(i, inf));
}
else{
pii last = mp(0, 0);
while(S.back().se < b[i]){
last = S.back();
S.pop_back();
}
if(b[i] != last.se + 1)
return cout << "-1\n", 0;
if(last.fi){
G[last.fi].pb(i);
d[i] ++;
}
G[i].pb(S.back().fi);
d[S.back().fi] ++;
if(S.back().se == b[i]){
S.pop_back();
}
S.pb(mp(i, b[i]));
}
}
for(int i = 1; i <= n; i ++)
if(!vis[i])
dfs(i);
for(int i = 1; i <= n; i ++)
if(!d[i])
Q.push(i);
for(int i = 1; i <= n; i ++){
int ind = Q.top();
Q.pop();
a[ind] = i;
for(int u : G[ind])
if(!(--d[u]))
Q.push(u);
}
for(int i = 1; i <= n; i ++)
cout << a[i] << ' ';
cout << '\n';
}
