#include <cstdio>
#include <random>
#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <cassert>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
#include <functional>
#include <chrono>


#define ll long long
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
using namespace std;

// вправо, вниз, влево, вверх
int dx[] = {0, 1, 0, -1};
int dy[] = {1, 0, -1, 0};

// ход конем
//int dx[] = {-2, -1, 1, 2, 2, 1, -1, -2};
//int dy[] = {1, 2, 2, 1, -1, -2, -2, -1};

mt19937 rnd(chrono::system_clock::now().time_since_epoch().count());
mt19937_64 rnd64(chrono::system_clock::now().time_since_epoch().count());
int rndInteger (int l, int r) {
    return uniform_int_distribution<int> (l, r)(rnd);
}

const int MOD = (int) 1e9 + 7;
const int N = (int) 2e5 + 7;

int mult(int a, int b) {
    return a * (ll)b % MOD;
}

int add(int a, int b) {
    a += b;
    if(a < 0) a += MOD;
    if(a >= MOD) a -= MOD;
    return a;
}

int bpow(int a, int b) {
    int res = 1;
    while(b > 0) {
        if(b&1) res = mult(res, a);
        b >>= 1;
        a = mult(a, a);
    }

    return res;
}

inline int g(int x) {
    if(x == 0)
        return 0;

    int sqr = mult(x, x);
    int cub = mult(sqr, x);
    return add(mult(2, cub), mult(3, add(sqr, x+1)));
}
int G[N];

int n, m;
int c[N];
int pref[N][55];
int f[N];
int last[55];
int pw[N];
int inv_pw[N];

inline void solve(){
    cin >> n >> m;
    for (int i = 1; i <= n; ++i) {
        cin >> c[i];

        for (int j = 1; j <= m; ++j)
            pref[i][j] = pref[i-1][j];

        pref[i][c[i]]++;
    }
    int inv2 = bpow(2, MOD - 2);
    pw[0] = inv_pw[0] = 1;

    for (int i = 1; i <= n; ++i) {
        pw[i] = mult(pw[i-1], 2);
        inv_pw[i] = mult(inv_pw[i-1], inv2);
    }

    G[1] = g(1);
    for (int i = 2; i <= n; ++i) {
//        G[i] = g(i) - 2*G[i-1] + G[i-2];
        G[i] = g(i) - 2*g(i-1) + g(i-2);
    }

    for (int i = 1; i <= n; ++i) {
        f[i] = add(f[i-1], mult(G[i], inv_pw[i]));
    }

//    for (int i = 1; i <= n; ++i) {
//        cout << "g: G: " << g(i) << ' ' << G[i] << '\n';
//    }

    int ans = 0;
    vector<int> Ls;
    for (int r = 1; r <= n; ++r) {
        if(last[c[r]]) Ls.erase(find(all(Ls), last[c[r]]));
        Ls.push_back(r);
        last[c[r]] = r;
//        int outside = 1;
//        for (int col = 1; col <= m; ++col) {
//            outside = mult(outside, pw[pref[n][col]] - 1);
//        }


        for (int ii = (int)Ls.size() - 1; ii >= 0; --ii) {
            int l = Ls[ii];
            int cur = 1;
            for (int col = 1; col <= m; ++col) {
                int cnt = pref[r][col] - pref[l - 1][col];

                if(cnt) cur = mult(cur, pw[pref[n][col] - cnt]);
                else cur = mult(cur, pw[pref[n][col]] - 1);
            }

            int L = r - l + 1;
            int R = r - (ii == 0 ? 0 : Ls[ii - 1]);

            //cur * g(L)
            int now = 0;
            now = add(now, add(f[R], -f[L-1]));
            now = mult(now, pw[L]);
//            for (int len = L; len <= R; ++len) {
//                now = add(now, mult(inv_pw[len - L], G[len]));
//            }

            now = mult(now, cur);
            ans = add(ans, now);
        }
    }



    cout << ans << '\n';
}

int main() {
#ifdef LOCAL
    freopen("in.txt", "r", stdin);
#endif

    ios_base::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int TestCases = 1;
//    cin >> TestCases;

    for (int TestCase = 1; TestCase <= TestCases; ++TestCase) {
//        cout << "Case #" << TestCase << ": ";

        solve();
    }


    return 0;
}