#include <bits/stdc++.h>
#define FOR(i, begin, end) for(int i=(begin);i<(end);i++)
#define REP(i, n) FOR(i,0,n)
#define IFOR(i, begin, end) for(int i=(end)-1;i>=(begin);i--)
#define IREP(i, n) IFOR(i,0,n)
#define Sort(a) sort(a.begin(), a.end())
#define Reverse(a) reverse(a.begin(), a.end())
#define Lower_bound(v, x) distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x) distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define Ans(f, y, n) if(f) cout << y << endl; else cout << n << endl;
#define int long long
#define INF 1000000000000000000
using namespace std;

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;

template<typename T>
void readv(vector<T> &a){ REP(i, a.size()) cin >> a[i]; }
void readi(vector<int> &a){ REP(i, a.size()){cin >> a[i]; a[i]--;} }
template<typename T>
void debug(vector<vector<T>> m){ REP(i, m.size()){ REP(j, m[i].size()){ cout << m[i][j] << ","; } cout << endl;} }

int modpow(int x, int n, int m){
    int a = 1;
    IREP(i, 64){
        a = (a * a) % m;
        if(((n >> i) & 1) == 1) a = (a * x) % m;
    }
    return a;
}

class Combination
{
public:

    vec fact, invfact;
    int MAX_N, mod;

    Combination(int MAX_N, int mod): MAX_N(MAX_N), mod(mod) {
        initialize();
    }

    void initialize(){
        fact = vec(MAX_N + 1);
        invfact = vec(MAX_N + 1);
        fact[0] = 1;
        FOR(i, 1, MAX_N + 1){
            fact[i] = (fact[i - 1] * i) % mod;
        }
        invfact[MAX_N] = modpow(fact[MAX_N], mod - 2, mod);
        IREP(i, MAX_N){
            invfact[i] = (invfact[i + 1] * (i + 1)) % mod;
        }
    }

    int nCr(int n, int r){
        if(r > n || r < 0 || n < 0) return 0;
        if(n > MAX_N){
            MAX_N = n;
            initialize();
        }
        int a = fact[n];
        a = (a * invfact[r]) % mod;
        a = (a * invfact[n - r]) % mod;
        return a;
    }

    int nPr(int n, int r){
        if(r > n || r < 0 || n < 0) return 0;
        if(n > MAX_N){
            MAX_N = n;
            initialize();
        }
        int a = fact[n];
        a = (a * invfact[n - r]) % mod;
        return a;
    }
};

signed main(){

    int N, K, M; cin >> N >> K >> M;
    vec A(M); readi(A);
    int mod = 1000000007;
    Combination comb(K, mod);

    bool c = false, f = false;
    vec cnt(K, 0);
    set<int> s;
    REP(i, M){
        cnt[A[i]]++;
        if(cnt[A[i]] == 1) s.insert(A[i]);
        if(i >= K){
            cnt[A[i - K]]--;
            if(cnt[A[i - K]] == 0) s.erase(A[i - K]);
        }
        if(cnt[A[i]] > 1) f = true;
        if(s.size() == K) c = true;
    }

    int ans = 0;
    //Aがcolorful
    if(c){
        ans = 0;
    }else if(f){
        //A内に距離K以内の重複する要素あり
        int l, r;
        s.erase(s.begin(), s.end());
        REP(i, M){
            if(s.count(A[i])){
                l = i;
                break;
            }else s.insert(A[i]);
        }
        s.erase(s.begin(), s.end());
        REP(i, M){
            if(s.count(A[M - i - 1])){
                r = i;
                break;
            }else s.insert(A[M - i - 1]);
        }

        mat dp(N + 1, vec(K, 0));
        dp[0][0] = 1;
        REP(i, N){
            REP(j, K - 1){
                dp[i + 1][j + 1] += dp[i][j] * (K - j);
                dp[i + 1][j + 1] %= mod;
            }
            int tmp = 0;
            IFOR(j, 1, K){
                tmp += dp[i][j];
                dp[i + 1][j] += tmp;
                dp[i + 1][j] %= mod;
            }
        }

        REP(i, N - M + 1){
            int s1 = 0, s2 = 0;
            FOR(j, l, K) s1 += dp[i + l][j];
            FOR(j, r, K) s2 += dp[N - M - i + r][j];
            s1 %= mod; s2 %= mod;
            ans += s1 * s2;
            ans %= mod;
        }
        ans *= modpow(comb.nPr(K, l), mod - 2, mod);
        ans %= mod;
        ans *= modpow(comb.nPr(K, r), mod - 2, mod);
        ans %= mod;
    }else{
        //A内に重複なし
        vector<mat> dp(2, mat(N + 1, vec(K, 0)));
        dp[0][0][0] = 1;
        REP(i, N){
            REP(t, 2){
                REP(j, K - 1){
                    dp[t][i + 1][j + 1] += dp[t][i][j] * (K - j);
                    dp[t][i + 1][j + 1] %= mod;
                }
                int tmp = 0;
                IFOR(j, 1, K){
                    tmp += dp[t][i][j];
                    dp[t][i + 1][j] += tmp;
                    dp[t][i + 1][j] %= mod;
                }
            }
            FOR(j, M, K){
                dp[1][i + 1][j] += dp[0][i + 1][j];
                dp[1][i + 1][j] %= mod;
            }
        }
        REP(j, K) ans += dp[1][N][j];
        ans %= mod;
        ans *= modpow(comb.nPr(K, M), mod - 2, mod);
        ans %= mod;
    }

    ans = (((N - M + 1) * modpow(K, N - M, mod)) % mod - ans + mod) % mod;
    cout << ans << endl;
    
    return 0;
}

Measured memory_bytes: 237568