#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
void solve() {
LL n, m;
cin >> n >> m;
vector<LL> a(n + m - 1), b(n + m - 1);
LL sum = 0;
for (LL i = 0; i < n + m - 1; i++) {
cin >> a[i];
sum += a[i];
}
for (LL i = 0; i < n + m - 1; i++) {
cin >> b[i];
sum += b[i];
}
// Special case: 1×M or N×1 grid
if (n == 1 || m == 1) {
LL total = 0;
for (LL i = 0; i < n; i++) {
for (LL j = 0; j < m; j++) {
LL d1 = i - j + (m - 1); // index into a
LL d2 = i + j; // index into b
total += min(a[d1], b[d2]);
}
}
cout << total << "\n";
return;
}
// Build padded diagonal arrays Ax, Bx
LL diff = llabs(n - m);
LL L = max(n, m);
vector<LL> Ax, Bx;
if (n >= m) {
// pad A in front, append a[], pad B at back
Ax.insert(Ax.end(), diff, 0);
Ax.insert(Ax.end(), a.begin(), a.end());
Bx.insert(Bx.end(), b.begin(), b.end());
Bx.insert(Bx.end(), diff, 0);
} else {
// n < m: pad A at back, pad B in front
Ax.insert(Ax.end(), a.begin(), a.end());
Ax.insert(Ax.end(), diff, 0);
Bx.insert(Bx.end(), diff, 0);
Bx.insert(Bx.end(), b.begin(), b.end());
}
// Helper to compute the "mex" contribution on a given parity
auto compute_mex = [&](bool take_even_indices){
vector<LL> U, V;
for (LL i = 0; i < (LL)Ax.size(); i++) {
if ((i % 2 == 0) == take_even_indices) U.push_back(Ax[i]);
if ((i % 2 == 0) == (L % 2 == 1 ? take_even_indices : !take_even_indices))
V.push_back(Bx[i]);
}
if (U.size() < V.size()) swap(U, V);
LL k = U.size() / 2;
// fold pairs from ends
for (LL i = 0; i < k; i++) {
U[i] += U[U.size() - 1 - i];
}
for (LL i = 0; i < (LL)V.size() / 2; i++) {
V[i] += V[V.size() - 1 - i];
}
// prefix sums
for (LL i = 1; i <= k; i++) {
U[i] += U[i - 1];
V[i] += V[i - 1];
}
// insert zero at front for alignment
U.insert(U.begin(), 0);
V.insert(V.begin(), 0);
LL best = 0;
for (LL i = 0; i <= k; i++) {
best = max(best, U[i] + V[k - i]);
}
return best;
};
LL mex1 = compute_mex(true);
LL mex2 = compute_mex(false);
cout << (sum - mex1 - mex2) << "\n";
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
// single test case
solve();
return 0;
}
