#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn = 4e5 + 5;
struct segmenttree {
vector<ll> st;
vector<ll> lazy;
int n;
void init(int _n) {
n = _n;
st.assign(4 * n + 5, 0);
lazy.assign(4 * n + 5, 0);
}
#define lc id << 1
#define rc id << 1 | 1
void push(int id, int l, int r) {
st[id] += lazy[id];
if (l != r) {
lazy[lc] += lazy[id];
lazy[rc] += lazy[id];
}
lazy[id] = 0;
}
void modify(int L, int R, ll v, int id, int l, int r) {
push(id, l, r);
if (R < l || r < L)
return;
if (L <= l && r <= R) {
lazy[id] += v;
push(id, l, r);
return;
}
int mid = (l + r) / 2;
modify(L, R, v, lc, l, mid);
modify(L, R, v, rc, mid + 1, r);
st[id] = min(st[lc], st[rc]);
}
void update(int pos, ll v, int id, int l, int r) {
push(id, l, r);
if (r < pos || pos < l)
return;
if (l == r) {
st[id] = min(st[id], v);
return;
}
int mid = (l + r) / 2;
update(pos, v, lc, l, mid);
update(pos, v, rc, mid + 1, r);
st[id] = min(st[lc], st[rc]);
}
ll getmin(int L, int R, int id, int l, int r) {
push(id, l, r);
if (R < l || r < L)
return 1e17;
if (L <= l && r <= R)
return st[id];
int mid = (l + r) / 2;
return min(getmin(L, R, lc, l, mid), getmin(L, R, rc, mid + 1, r));
}
void modify(int l, int r, ll v) {
modify(l, r, v, 1, 0, n);
}
ll getmin(int l, int r) {
return getmin(l, r, 1, 0, n);
}
void set(int pos, ll v) {
update(pos, v, 1, 0, n);
}
};
ll solve(vector<int> a, vector<int> b, vector<pair<int, int>> query) {
int n = a.size(), m = b.size();
#ifdef LOCAL
for (int i : a) cerr << i << ' '; cerr << '\n';
for (int i : b) cerr << i << ' '; cerr << '\n';
for (auto & it : query) cerr << it.first << ' ' << it.second << '\n';
#endif // LOCAL
vector<int> order;
for (int i = 1; i < n; ++i)
order.push_back(i);
sort(order.begin(), order.end(), [&](int x, int y) {
return query[x - 1].first < query[y - 1].first;
});
vector<ll> sum(m + 5);
for (int i = 1; i < m; ++i)
sum[i] = sum[i - 1] + b[i];
segmenttree st1;
segmenttree st2;
st1.init(m); st2.init(m);
st1.modify(1, m, 1e15);
st2.modify(1, m, 1e15);
auto castdp = [&](int idx) {
//cerr << idx << ' ';
int l = query[idx - 1].first, r = query[idx - 1].second;
ll v1 = st1.getmin(0, l - 1);
ll v2 = st2.getmin(l, r);
st1.modify(0, r, a[idx]);
st2.modify(0, r, a[idx]);
st1.set(r, v1 + sum[r] - sum[l - 1]);
st2.set(r, v1 + sum[r] - sum[l - 1] - sum[r]);
st1.set(r, v2 + sum[r]);
st2.set(r, v2 + sum[r] - sum[r]);
};
for (int i : order) {
castdp(i);
}
return st1.getmin(0, m);
}
int N, M;
int a[maxn], b[maxn];
int L[maxn], R[maxn];
signed main(void) {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("A.INP", "r", stdin);
freopen("A.OUT", "w", stdout);
#endif // LOCAL
cin >> N >> M;
int l = M , r = M;
int v1 = 1, v2 = 1;
for (int i = 1; i <= N + M - 1; ++i) {
cin >> a[i];
L[i] = l; R[i] = r;
//cerr << l << ' ' << r << '\n';
l -= v1; r += v2;
if (l == 0) {
l += 2;
v1 = -v1;
}
if (r > N + M - 1) {
r -= 2;
v2 = -v2;
}
}
for (int i = 1; i <= N + M - 1; ++i)
cin >> b[i];
ll res = 0;
{
vector<int> A, B;
vector<pair<int, int>> query;
bool ok = false;
A.push_back(0); B.push_back(0);
for (int i = 1; i <= N + M - 1; ++i) {
if (i % 2 == 1) {
A.push_back(a[i]);
if (L[i] & 1) ok = true;
query.push_back(make_pair((L[i] + 1) / 2, (R[i] + 1) / 2));
}
}
for (int i = 1; i <= N + M - 1; ++i) {
if (ok) {
if (i % 2 == 1) {
B.push_back(b[i]);
}
} else {
if (i % 2 == 0) {
B.push_back(b[i]);
}
}
}
res += solve(A, B, query);
}
{
vector<int> A, B;
vector<pair<int, int>> query;
bool ok = false;
A.push_back(0); B.push_back(0);
for (int i = 1; i <= N + M - 1; ++i) {
if (i % 2 == 0) {
A.push_back(a[i]);
if (L[i] & 1) ok = true;
query.push_back(make_pair((L[i] + 1) / 2, (R[i] + 1) / 2));
}
}
for (int i = 1; i <= N + M - 1; ++i) {
if (ok) {
if (i % 2 == 1) {
B.push_back(b[i]);
}
} else {
if (i % 2 == 0) {
B.push_back(b[i]);
}
}
}
res += solve(A, B, query);
}
cout << res;
}
