#include <bits/stdc++.h>
using namespace std;
constexpr int INF = (1 << 30) - 1;
struct fraction {
int nom, denom;
fraction() = default;
fraction(int x) : nom(x), denom(1) {}
fraction(int x, int y) : nom(x), denom(y) {}
};
int sign(fraction a) {
if (a.nom == 0) {
return 0;
} else {
bool neg = (a.nom < 0) ^ (a.denom < 0);
return neg ? -1 : +1;
}
}
bool operator<(fraction a, fraction b) {
int sa = sign(a), sb = sign(b);
if (sa != sb) {
return sa < sb;
}
if (sa > 0) {
return 1LL * abs(a.nom) * abs(b.denom) < 1LL * abs(a.denom) * abs(b.nom);
} else {
return 1LL * abs(a.nom) * abs(b.denom) > 1LL * abs(a.denom) * abs(b.nom);
}
}
fraction intersect(int k1, int b1, int k2, int b2) {
return fraction(b2 - b1, k1 - k2);
}
vector<int> convex_hull(vector<int> A) {
vector<int> hull = {0};
vector<fraction> points = {fraction(INF)};
for (int i = 1; i < int(A.size()); i++) {
while (!hull.empty() && !(intersect(i, A[i], hull.back(), A[hull.back()]) < points.back())) {
points.pop_back();
hull.pop_back();
}
points.push_back(intersect(i, A[i], hull.back(), A[hull.back()]));
hull.push_back(i);
}
return hull;
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int H, W;
cin >> H >> W;
vector<int> A(H), B(W);
for (int &value : A) {
cin >> value;
}
for (int &value : B) {
cin >> value;
}
vector<int> A_hull = convex_hull(A);
vector<int> B_hull = convex_hull(B);
long long answer = 0;
int i = 0, j = 0;
int x = 0, y = 0;
while (i + 1 < int(A_hull.size()) && j + 1 < int(B_hull.size())) {
fraction P = intersect(A_hull[i], A[A_hull[i]], A_hull[i + 1], A[A_hull[i + 1]]);
fraction Q = intersect(B_hull[j], B[B_hull[j]], B_hull[j + 1], B[B_hull[j + 1]]);
if (!(P < Q)) {
answer += 1LL * B[y] * (A_hull[i + 1] - x);
x = A_hull[i + 1];
++i;
} else {
answer += 1LL * A[x] * (B_hull[j + 1] - y);
y = B_hull[j + 1];
++j;
}
}
while (i + 1 < int(A_hull.size())) {
answer += 1LL * B[y] * (A_hull[i + 1] - x);
x = A_hull[i + 1];
++i;
}
while (j + 1 < int(B_hull.size())) {
answer += 1LL * A[x] * (B_hull[j + 1] - y);
y = B_hull[j + 1];
++j;
}
cout << answer << "\n";
}
