#include <bits/stdc++.h>
using std::cin;
using std::cout;

typedef unsigned long long u64;
const int N = 4054;

int n, mod;
int a[N];
int f[N], g[N];

inline void add(int &x, const int y) {x += y - mod, x += x >> 31 & mod;}

void work() {
	int i, j, ans = 0; u64 x;
	cin >> n >> mod;
	for (i = 0; i < n; ++i) cin >> a[i];
	f[1] = *g = mod - 1;
	for (i = 1; i <= n; ++i) {
		add(f[i + 1] = f[i], f[i - 1]), x = f[i + 1], g[i] = x * g[i - 1] % mod;
		for (j = i - 1; j; --j) g[j] = (g[j] + x * g[j - 1]) % mod;
	}
	for (i = 0; i < n; ++i) ans = (ans + (u64)a[i] * g[n - i]) % mod;
	cout << ans << '\n';
}

int main() {
	int T;
	//std::ios::sync_with_stdio(false), cin.tie(NULL);
	//for (cin >> T; T; --T)
	work();
	return 0;
}