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

bool check(vector<int> &a, int n, int h, int mid)
{

    for (int i = 1; i < n; i++)
    {
        h -= min(a[i] - a[i - 1], mid);
        if (h <= 0)
            return true;
    }

    if (h <= mid)
        return true;
    return false;
}

int minimumJugCapacity(int N, int H, vector<int> &A)
{
    int start = 1;
    int end = H;
    int ans = 0;
    while (start <= end)
    {
        int mid = (start + end) / 2;
        if (check(A, N, H, mid))
        {
            ans = mid;
            end = mid - 1;
        }
        else
        {
            start = mid + 1;
        }
    }
    return ans;
}

int main()
{
    int N, H;
    cin >> N >> H;

    vector<int> A(N);
    for (int i = 0; i < N; i++)
        cin >> A[i];
    cout << minimumJugCapacity(N, H, A) << endl;
}