#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = (ll)1e9 + 7;

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	int n, m;
	cin >> n >> m;
	int h = 1 << n;

	vector<int> cs(h);
	for (int& c : cs) cin >> c;

	vector<pair<int, int>> itv(m);
	for (int i = 0; i < m; ++i) itv[i] = {h, -1};
	for (int i = 0; i < h; ++i) {
		int v = cs[i] - 1;
		itv[v].first = min(itv[v].first, i);
		itv[v].second = max(itv[v].second, i);
	}
	sort(itv.begin(), itv.end());

	ll res = 1;
	int lst = -1;
	for (int i = 0; i < m; ++i) {
		int a = itv[i].first;
		int b = itv[i].second;
		if (lst >= a) res = 0;
		lst = b;

		int len = b - a + 1;
		if (__builtin_popcount(len) > 1) res = 0;
		if (a % len != 0) res = 0;

		res = (res * len) % MOD;
	}
	cout << res << '\n';
}