//#include "paint.h"
#include <bits/stdc++.h>
#define pair<int,int>
using namespace std;
const int NN=1e5+100;
bool freq[NN];
vector<int> like[NN];
vector<int> c;
vector<int> a;
int mp2[NN];
int mp3[NN];
vector<int> vis;
vector<int> vis2;
int n,m,k;
map<int,bool> mp[NN];
bool ok(int x,int y)
{
for(int l=0;l<m;l++){
if(mp[(x+l)%m][c[y+l]]==0){
return 0;
}
}
return 1;
}
int minimumInstructions(
int N, int M, int K, std::vector<int> C,
std::vector<int> A, std::vector<std::vector<int>> B)
{
a=A;
c=C;
n=N;
m=M;
k=K;
int maxx=0;
// cout<<5<<endl;
for(int i=0;i<m;i++){
for(auto x:B[i]){
mp[i][x]=1;
like[x].push_back(i);
}
}
for(int i=0;i<k;i++){
maxx=max(maxx,(int)like[i].size());
}
// cout<<5<<endl;
int idx=-1;
int cnt=0;
if(maxx<=1){
for(int i=0;i<n;i++){
int v=c[i];
if(like[v].empty())return -1;
if(like[v][0]==idx){
cnt++;
}
else{
cnt=1;
idx=like[v][0];
}
if(cnt>=m){
freq[i-m+1]=1;
}
idx++;
idx%=m;
}
}
else if(n<=-1){
for(int j=0;j<=n-m;j++){
for(auto i:like[c[j]]){
if(ok(i,j)){
freq[j]=1;
break;
}
}
}
}
else{
for(int i=0;i<n;i++){
int mox=0;
for(auto x:like[c[i]]){
mp2[x]=mp3[(x-1+m)%m]+1;
mox=max(mox,mp2[x]);
vis.push_back(x);
}
if(mox>=m){
freq[i-m+1]=1;
}
for(auto x:vis2){
mp3[x]=0;
}
for(auto x:vis){
mp3[x]=mp2[x];
mp2[x]=0;
}
vis2.clear();
vis2=vis;
vis.clear();
}
}
int mx=0;
int ans=0;
int i=0;
// cout<<5<<endl;
while(mx<n){
int v=mx;
// cout<<mx<<endl;
ans++;
while(i<=mx){
if(freq[i]){
v=max(v,i+m);
}
i++;
}
if(v==mx)break;
mx=v;
}
if(mx<n)return -1;
return ans;
}
/*
int main() {
int N, M, K;
assert(3 == scanf("%d %d %d", &N, &M, &K));
std::vector<int> C(N);
for (int i = 0; i < N; ++i) {
assert(1 == scanf("%d", &C[i]));
}
std::vector<int> A(M);
std::vector<std::vector<int>> B(M);
for (int i = 0; i < M; ++i) {
assert(1 == scanf("%d", &A[i]));
B[i].resize(A[i]);
for (int j = 0; j < A[i]; ++j) {
assert(1 == scanf("%d", &B[i][j]));
}
}
int minimum_instructions = minimumInstructions(N, M, K, C, A, B);
printf("%d\n", minimum_instructions);
return 0;
}
*/
/*
8 3 5
3 3 1 3 4 4 2 2
3 0 1 2
2 2 3
2 3 4
*/
