#include <stdio.h>
#define NMax 34568
const char IN[]="euro.in",OUT[]="euro.out";

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

int 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("%d",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<<61);
		for (j=1;j<=i && j*j<=4*T; ++j)
			D[i]=max(D[i],  P[i]*S[P[i]] - T + D[i-j] - P[i]*S[P[i-j]]); 
	}
	
	freopen(OUT,"w",stdout);
	printf("%lld\n",D[L]);
	fclose(stdout);
	
	return 0;
}