#include <bits/stdc++.h>

using namespace std;
int main() {
	int n,k; cin >> n >> k;
	vector<int> v(n);
	map<int, int> m;
	for (int i = 0; i < n; i++)
		cin >> v[i];
	int a = 0;
	for (int i = 0; i < n; i++)
	{
		m[a] += v[i];
		a = (a + 1 )% k;
	}

	long long ans = 0 ;
	int ma = 0;
	
	for (auto x : m)
	{
	  
		ma = max(ma, x.second);
		ans += x.second;
	}
	cout << ans - ma;
}