#include<cstdio>
#include<cmath>
#include<iostream>
using namespace std;
int a[505][505],c[505][505],f[505][505];
int main()
{
int m,n;
scanf("%d%d",&m,&n);
for(int i = 1; i < m; ++i)
scanf("%d",&a[i][i+1]);
for(int i = 1; i <= m; ++i)
{
for(int j = i+1; j <= m; ++j)
{
a[i][j] = a[j-1][j] + a[i][j-1];
a[j][i] = a[i][j];
}
}
int mid;
for(int i = 1; i <= m; ++i)
{
for(int j = i+1; j <= m; ++j)
{
mid=(i+j)/2;
c[i][j] = 0;
for(int k = i; k <= j; ++k)
c[i][j] += a[k][mid];
}
}
for(int i = 1; i <= m; ++i)
f[i][1] = c[1][i];
int s = 0x7fffffff;
for(int i = 1; i <= m; ++i)
{
for(int j = 2; j <= n; ++j)
{
f[i][j] = s;
for(int k = j-1; k <= i; ++k)
f[i][j] = min(f[i][j],f[k][j-1]+c[k+1][i]);
}
}
printf("%d",f[m][n]);
return 0;
}
