#include <bits/stdc++.h>   using namespace std;   int Max = INT_MIN, Min = INT_MAX;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     ;     int n, m, mx = 0;     cin >> n >> m;     int a[n];     for (int i = 0; i < n; i++) cin >> a[i];     for (int i = 0; i < n - 1; i++) {       if ((a[i] - a[i + 1] - m) > mx) {         mx = (a[i] - a[i + 1] - m);       }     }     cout << ((mx > 0) ? mx : 0);     return 0;   }   