1 #include <iostream>
 2 #include <cstdio>
 3 using namespace std;
 4 const int maxn=500010;
 5 long long f[maxn],s[maxn];
 6 int q[maxn]; 
 7 int main()
 8 {
 9     int n,m,front,back;
10     while(~scanf("%d%d",&n,&m))
11     {
12         s[0]=f[0]=0;
13         for(int i=1;i<=n;i++)scanf("%d",&s[i]);
14         for(int i=2;i<=n;i++)s[i]+=s[i-1];
15         
16         front=1;back=2;
17         q[front]=0;
18         
19         for(int i=1;i<=n;i++)
20         {
21             while(front<back-1&&(f[q[front+1]]+s[q[front+1]]*s[q[front+1]])-(f[q[front]]+s[q[front]]*s[q[front]])<=2*s[i]*(s[q[front+1]]-s[q[front]])) front++;
22             
23             f[i]=f[q[front]]+(s[i]-s[q[front]])*(s[i]-s[q[front]])+m;
24             
25             while(front<back-1&&(s[q[back-1]]-s[q[back-2]])*((f[i]+s[i]*s[i])-(f[q[back-1]]+s[q[back-1]]*s[q[back-1]]))<=(s[i]-s[q[back-1]])*((f[q[back-1]]+s[q[back-1]]*s[q[back-1]])-(f[q[back-2]]+s[q[back-2]]*s[q[back-2]])))back--;
26             q[back++]=i;
27         }
28         printf("%lld\n",f[n]);
29     }
30     return 0;
31 }