#include<bits/stdc++.h>

using namespace std;

const int maxn = 101;
int main() {
	int n, m, a[maxn],b[maxn];
	cin >> n >> m;
	memset(a,0,sizeof(a));
	memset(b,0,sizeof(b));
	for (int i = 0; i < n; i++) {
		cin >> a[maxn];
	}
	for (int i = 0; i < n; i++) {
		int j = i;
		while (j < m) {
			b[i] += a[j];
			j++;
		}
	}
	int min = b[0];
	for (int i = 0; i < n; i++) {
		if (b[i] < min) {
			min = b[i];
		}
	}
	cout << min;
	return 0;
}

求大佬指点