#include<bits/stdc++.h>
#define L(i, j, k) for(int i = (j); i <= (k); ++i)
#define R(i, j, k) for(int i = (j); i >= (k); --i)
#define ll long long
#define sz(a) (int)(a).size()
#define pb push_back
#define mk make_pair
#define fir first
#define sec second

using namespace std;
const int N = 305;
const ll M = 1e9 + 7;
int n, K;
int c[N];
ll g[N][N], dp[N][N], f[N][N], G[N];
ll ksm(ll aa, ll bb){
    if(bb < 0) return 1;
    ll as = 1;
    while(bb) {
        if(bb & 1) as = as * aa %M;
        aa = aa * aa  %M; bb >>= 1;
    }
    return as;
}
ll jx[N], ny[N];
ll C(int nn, int mm){
    if(nn < mm) return 0;
    return (jx[nn] * ny[nn - mm]%M)* ny[mm] %M;
}
int main(){

    ios :: sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    cin >> n >>  K;
    jx[0] = ny[0] = 1;
    L(i, 1, n){
        jx[i] = jx[i - 1] * i %M;
        ny[i] = ksm(jx[i], M - 2);
    }
    int u;
    L(i, 1 ,n) {
        cin >> u; c[u] ++; 
    }
    L(i, 1, n){
        if(c[i] == n){
            if(n <= K) return cout << ksm(n, n - 2), 0;
            else return cout << 0, 0;
        } 
    }
    g[0][0] = 1;
    L(i, 1, n){
        L(j, 1, i){
            L(k, 0, min(i - 1, K - 1)){
                if(!g[i - k - 1][j - 1]) continue;
                // if(i == j && j == 4)cerr << g[i - k - 1][j - 1] <<"!\n";
                g[i][j] += ((C(i - 1, k) * g[i - k - 1][j - 1] %M) * ksm(k + 1, k - 1) %M) * (k + 1);
                g[i][j] %= M;
            }
        }
    }
    L(i, 1 ,n) {
        g[i][1] *= ksm(i, M - 2); g[i][1] %= M;
        L(j, 1, i){
            g[i][j] *= ksm(i, j - 2);  g[i][j] %= M;
            // if(g[i][j]) cerr << i <<" " << j << " " << g[i][j] << "\n";
        }
    }
    L(i, 1, n){
        L(j, 1, i){
            if(j % 2 == 0) G[i] -= g[i][j];
            else G[i] += g[i][j];
            G[i] %= M;
        }
        // cerr << G[i] <<" ";
        if(G[i] < 0) G[i] += M;
    }
    dp[0][0] = 1;
    L(i, 1, n){
        L(j, 1, i){
            L(k, 0, i - 1){
                dp[i][j] += (C(i - 1, k) * dp[i - k - 1][j - 1]%M) * (G[k + 1] * (k + 1) %M);
                dp[i][j] %= M;
            }
        }
    }
    f[0][0] = 1;
    L(i, 1, n){
        if(c[i]){
            L(j, 1, n){
                L(k, 1, min(c[i], j)){
                    f[i][j] += (f[i - 1][j - k] * dp[c[i]][k] ) ;
                    f[i][j] %= M;
                }
            }
        }
        else {
            L(j, 1, n) f[i][j] = f[i - 1][j]; 
        }
    }
    ll ans = 0;
    L(j, 2, n){
        if(!f[n][j]) continue;
        ans += f[n][j] * ksm(n, j - 2);
        ans %= M;
    }
    cout << ans;
    return 0;
}