#include <bits/stdc++.h>
using namespace std;
#define dbgv(v) cout<<#v<<" = "; f(i,0,v.size()) cout<<v[i]<<" "; cout<<endl
#define dbga(a,x,y) cout<<#a<<" = "; f(i,x,y) cout<<a[i]<<" "; cout<<endl
#define erorp(x) cout<<#x<<"={"<<x.F<<" , "<<x.S<<"}"<<endl
#define eror(x) cout<<#x<<'='<<(x)<<endl
#define f_(i,a,b) for(int i=a;i>=b;i--)
#define f(i,a,b) for(int i=a;i<b;i++)
#define nb(x) __builtin_popcount(x)
#define all(v) v.begin(),v.end()
#define bit(n,k) (((n)>>(k))&1)
#define Add(x,y) x=(x+y)%mod
#define maxm(a,b) a=max(a,b)
#define minm(a,b) a=min(a,b)
#define lst(x) x[x.size()-1]
#define sz(x) int(x.size())
#define mp make_pair
#define ll long long
#define pb push_back
#define S second
#define F first
#include "paint.h"
const int N=1e5+99;
int n,m,k,a[N],ps[N],last[N],col[N],pfx[N],sfx[N],fenwik[N];
vector<int> vec[N];
void add(int x, int val){ for(x++;x<N;x+=x&-x) minm(fenwik[x],val); }
int get(int x) { int res=N; for (x++;x>0;x-=x&-x) minm(res,fenwik[x]); return res; }
int minimumInstructions(int _n, int _m, int _k,vector<int> C,vector<int> B,vector<std::vector<int>> A) {
n=_n,m=_m,k=_k;
f(i,0,n) col[i]=C[i],vec[col[i]].pb(i);
f(i,0,m){
for(auto x : A[i]){
for(auto indx : vec[x]){
if(a[indx-1]==i || last[indx-1]==i){
last[indx]=a[indx];
a[indx]=i+1;
pfx[indx-i]=i+1;
}
}
}
}
f(i,0,N) a[i]=last[i]=0;
f(i,0,m){
for(auto x : A[m-i-1]){
for(auto indx : vec[x]){
if(a[indx+1]==i || last[indx+1]==i){
last[indx]=a[indx];
a[indx]=i+1;
sfx[indx+i]=i+1;
}
}
}
}
//dbga(pfx,0,n);
//dbga(sfx,0,n);
f(i,0,n+1){
int l,r=i+pfx[i];
if(i==0) l=0;
else l=i-sfx[i-1];
r-=m;
if(l<=r) ps[l]++,ps[r+1]--;
}
f(i,0,n) ps[i]+=ps[i-1];
fill(fenwik,fenwik+N,N);
add(n,0);
f_(i,n-m,0){
if(ps[i]){
int res=get(i+m)+1;
add(i,res);
}
}
if(get(0)==N) return -1;
return get(0);
}
/*
int32_t main(){
ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
int n,m,k;
vector<int> C,A;
vector<vector<int>> B;
cin>>n>>m>>k;
f(i,0,n){
int x;
cin>>x;
C.pb(x);
}
f(i,0,m){
int x;
cin>>x;
A.pb(x);
}
f(i,0,m){
vector<int> v;
B.pb(v);
f(j,0,A[i]){
int x;
cin>>x;
B[i].pb(x);
}
}
cout<<minimumInstructions(n,m,k,C,A,B);
}*/
/*
8 3 5
3 3 1 3 4 4 2 2
3 2 2
0 1 2
2 3
3 4
*/
