#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<string>
#include<vector>
#include<stack>
#include<bitset>
#include<cstdlib>
#include<cmath>
#include<set>
#include<list>
#include<deque>
#include<map>
#include<queue>
#define ll long long int
using namespace std;
inline ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
inline ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
int moth[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int dir[4][2]={1,0 ,0,1 ,-1,0 ,0,-1};
int dirs[8][2]={1,0 ,0,1 ,-1,0 ,0,-1, -1,-1 ,-1,1 ,1,-1 ,1,1};
const int inf=0x3f3f3f3f;
const ll mod=1e9+7;
ll n,k;
ll a[100007];
ll dp[100007][2];
ll sum[100007];
ll q[100007];
double slope(ll j,ll k,ll zu){
return sum[k]-sum[j]==0?0:((dp[j][zu]-sum[j]*sum[j]-dp[k][zu]+sum[k]*sum[k])
/(sum[k]-sum[j]));
}
int main(){
ios::sync_with_stdio(false);
while(cin>>n>>k){
for(int i=1;i<=n;i++)
cin>>a[i],sum[i]=sum[i-1]+a[i];
int l,r;
for(int j=1;j<=k;j++){ //分割次数
l=r=1;
for(int i=1;i<=n;i++){ //人数
while(l<r&&slope(q[l],q[l+1],(j-1)%2)<sum[i]) l++;
dp[i][j%2]=dp[q[l]][(j-1)%2]+sum[q[l]]*(sum[i]-sum[q[l]]);
while(l<r&&slope(q[r-1],q[r],(j-1)%2)>slope(q[r],i,(j-1)%2)) r--;
q[++r]=i;
}
}
cout<<dp[n][k%2]<<endl;
}
return 0;
}