#include<cstdio>

 #include<cstring>

 #include<algorithm>

 #include<vector>

 #include<queue>

 #include<cmath>

 #define inf 0x3f3f3f3f

 #define LL long long int

 using namespace std;

 const int maxn=;

 inline LL rd(){

     LL x=;char c=getchar();int neg=;

     while(c<''||c>''){if(c=='-') neg=-;c=getchar();}

     while(c>=''&&c<='') x=x*+c-'',c=getchar();

     return x*neg;

 }

 int N;

 LL co[maxn],sm[maxn],f[maxn],L;

 int q[maxn],h,t;

 inline LL pw2(LL x){return x*x;}

 inline bool judge1(int j1,int j2,int i){

     return f[j1]+pw2(j1+sm[j1])-f[j2]-pw2(j2+sm[j2])<(*i+*sm[i]-*L-)*(j1+sm[j1]-j2-sm[j2]);

 }

 inline bool judge2(int j1,int j2,int j3){

     return (f[j1]+pw2(j1+sm[j1])-f[j2]-pw2(j2+sm[j2]))*(j2+sm[j2]-j3-sm[j3])<

            (f[j2]+pw2(j2+sm[j2])-f[j3]-pw2(j3+sm[j3]))*(j1+sm[j1]-j2-sm[j2]);

 }

 int main(){

     int i,j,k;

     N=rd();L=rd();

     for(i=;i<=N;i++)co[i]=rd(),sm[i]=sm[i-]+co[i];

     h=t=;q[]=;

     for(i=;i<=N;i++){

         while(h<t&&!judge1(q[h],q[h+],i)) h++;

         f[i]=f[q[h]]+pw2(i-q[h]-+sm[i]-sm[q[h]]-L);

         while(h<t&&!judge2(q[t-],q[t],i)) t--;

         q[++t]=i;

     }printf("%lld\n",f[N]);

     return ;

 }