#include <bits/stdc++.h>
using namespace std;
int dis[550][550]; // 村庄间距离
int scdis[550][500]; // 村庄间小学距离和
int dp[550][550];
int main()
{
int m, n;
cin >> m >> n;
for (int i = 1; i < m; i++)
{
cin >> dis[i][i + 1];
dis[i + 1][i] = dis[i][i + 1];
}
for (int i = 1; i < m; i++)
{
for (int j = i + 1; j <= m; j++)
{
dis[i][j] = dis[j][i] = dis[i][j - 1] + dis[j - 1][j];
}
}
for (int i = 1; i < m; i++)
{
for (int j = i + 1; j <= m; j++)
{
int mid = (i + j) / 2;
for (int k = i; k <= j; k++)
{
scdis[i][j] += dis[k][mid];
}
}
}
memset(dp, 0x3f, sizeof(dp));
for (int i = 1; i <= m; i++)
{
dp[i][1] = scdis[1][i]; // 从1到i之间建一个小学
}
for (int i = 1; i <= m; i++)
{
for (int j = 2; j <= n; j++)
{
for (int k = j - 1; k <= i; k++)
{
dp[i][j] = min(dp[i][j], dp[k][j - 1] + scdis[k + 1][i]);
}
}
}
cout << dp[m][n];
return 0;
}