#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef pair<int, int> ii;
const int INF = 0x3f3f3f3f;
const ll INFLL = 0x3f3f3f3f3f3f3f3fll;
#define each(x, s) for (auto& x : s)
#define loop(x) for (int i = 0;i < x;i++)
#define vloop(v, x) for (int v = 0;v < x;v++)
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define endl "\n"
int main() {
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
int m, n;
cin >> n >> m;
int d = n + m - 1;
vector<ll> a(d), b(d);
each(x, b) cin >> x;
each(x, a) cin >> x;
vector<tuple<int, int, ll>> is;
loop(d) {
int minr = max(0, i - m + 1);
int maxr = min(i, n - 1);
int maxc = i - minr;
int minc = i - maxr;
is.emplace_back(minr - maxc + m - 1, maxr - minc + m - 1, a[i]);
}
sort(iter(is));
loop(d - 2) b[i + 2] += b[i];
auto get = [&] (int l, int r) { return b[r] - (l - 2 >= 0 ? b[l - 2] : 0); };
vector<ll> dp(d + 1, 0);
int b0 = -2, b1 = -1;
loop(d) {
auto& [l, r, x] = is[i];
ll y = get(max(l, i & 1 ? b1 : b0), r);
if (x <= y) dp[i + 1] = dp[i] + x;
else {
dp[i + 1] = dp[i] + y;
b1 = r;
}
swap(b0, b1);
}
cout << dp[d] << endl;
return 0;
}
