#include <cstdio>

const int maxn = 50005;

int n, L, head_, tail;

long long s[maxn], f[maxn];

struct point {

	long long x, y;

	int id;

} que[maxn], t;

inline long long poww(long long aa) {

	return aa * aa;

}

inline long long g(int i) {

	return s[i] + i - L - 1;

}

inline long long h(int i) {

	return s[i] + i;

}

inline double getk(point & aa, point & ss) {

	return (double)(ss.y - aa.y) / (double)(ss.x - aa.x);

}

int main(void) {

	scanf("%d%d", &n, &L);

	for (int i = 1; i <= n; ++i) {

		scanf("%lld", s + i);

		s[i] += s[i - 1];

	}

	que[tail++] = (point){0, 0, 0};

	long long tem;

	int j;

	for (int i = 1; i <= n; ++i) {

		tem = g(i) << 1;

		while (tail - head_ > 1 && getk(que[head_ + 1], que[head_]) <= (double)tem) {

			++head_;

		}

		j = que[head_].id;

		f[i] = f[j] + poww(i - j - 1 + s[i] - s[j] - L);

		t = (point){h(i), f[i] + poww(h(i)), i};

		while (tail - head_ > 1 && getk(t, que[tail - 1]) <= getk(que[tail - 1], que[tail - 2])) {

			--tail;

		}

		que[tail++] = t;

	}

	printf("%lld\n", f[n]);

	return 0;

}