#include <fstream>

using namespace std;

ifstream fin("perle2.in");
ofstream fout("perle2.out");

int n,k,x,i,pc,smax,sc;

int main()
{
    fin>>n>>k;
    for(i=1;i<=n;i++)
    {
        fin>>x;
        if(sc<0)
        {
            sc=0;pc=i;
        }
        sc+=x-k;
        if(sc>smax)
            smax=sc;
    }
    fout<<max(smax,0);
    return 0;
}