#include<bits/stdc++.h>
#define int long long
using namespace std;
int n, m, a[2000006], sum[2000006];
inline int f(int p) {
	return p * (p + 1) / 2;
}
inline int solve(int l, int r) {
	int mid = (l + r) >> 1;
	return a[mid] * (2 * mid - l - r) - sum[mid - 1] + sum[l - 1] + sum[r] - sum[mid] - f(mid - l) - f(r - mid);
}
signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	sort(a + 1, a + n + 1);
	for (int i = 1; i <= n; i++) {
		a[i + n] = a[i] + m;
	}
	for (int i = 1; i <= 2 * n; i++) {
		sum[i] = sum[i - 1] + a[i];
	}
	int ans = 0x3f3f3f3f3f3f3f3f;
	for (int i = 1; i <= n; i++) {
		ans = min(ans, solve(i, i + n - 1));
//		cout << solve(i, i + n - 1) << endl;
	}
	cout << ans;
}