#include <stdio.h>
#define NMax 34600
const char IN[]="euro.in",OUT[]="euro.out";

int N,T,L;
long long v[NMax] , P[NMax] ;
long long S[NMax] , D[NMax] , Sum[NMax];

long long max(long long x,long long y){
	return x>y ? x : y;
}

int main()
{
	int i,j;
	freopen(IN,"r",stdin);
	scanf("%d%d",&N,&T);
	for (i=1,L=1;i<=N;++i)
	{
		scanf("%lld",v+i);
		S[i]=S[i-1]+v[i];
		if (Sum[L]<0) ++L;
		Sum[L]+=v[i];
		P[L]=i;
	}
	fclose(stdout);
	
	for (i=1;i<=L;++i)
	{
		D[i]= -(1LL<<62);
		for (j=0;j<=i && j*j<=4*T; ++j)
			D[i]=max(D[i],  P[i]*(S[P[i]]-S[P[i-j]]) - T + D[i-j] ); 
	}
	
	freopen(OUT,"w",stdout);
	printf("%lld\n",D[L]);
	fclose(stdout);
	
	return 0;
}