#include <bits/stdc++.h>
using namespace std;

#define nmax 52
#define dmax 10002

int n, e, d[nmax];
int best[nmax][dmax];
int dq[dmax], st, dr;

ifstream f("stalpi.in");
ofstream g("stalpi.out");

bool ok(int D)
{
	memset(best, 0x3f, sizeof best);
	best[1][0] = 0;

	for (int i = 2; i <= n; ++i)
	{
		st = 1;	dr = 0;

		for (int j = 0; j <= d[n]; ++j)
		{
			while (st <= dr && abs(j - dq[st]) > D)
				++st;

			while (st <= dr && best[i-1][dq[dr]] >= best[i-1][j])
				--dr;

			dq[++dr] = j;

			best[i][j] = abs(d[i] - j) + best[i-1][dq[st]];
			if (best[i][j] > best[0][0])
				best[i][j] = best[0][0];
		}
	}

	return (best[n][d[n]] <= e);
}

int main()
{
	f>>n>>e;

	for (int i = 2; i <= n; ++i)
		f>>d[i];

	int ret = d[n];

	for (int i = 1<<20; i > 0; i >>= 1)
        if (ret - i >= 0 && ok(ret - i))
            ret -= i;

	g<<ret;

    f.close();
    g.close();
	return 0;
}