#include <bits/stdc++.h>
using namespace std;
void just_do_it();
int main() {
#ifdef KAMIRULEZ
freopen("kamirulez.inp", "r", stdin);
freopen("kamirulez.out", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(0);
just_do_it();
return 0;
}
struct point {
long long x, y;
point(): x(0), y(0) {};
point(long long _x, long long _y): x(_x), y(_y) {};
};
point operator-(point p1, point p2) {
return point(p1.x - p2.x, p1.y - p2.y);
}
long long operator^(point p1, point p2) {
return p1.x * p2.y - p1.y * p2.x;
}
const int maxN = 1e5 + 20;
int A[maxN];
int B[maxN];
bool ccw(point p1, point p2, point p3) {
return ((p1 - p2) ^ (p3 - p2)) < 0;
}
vector<point> build(int A[], int N) {
point L(1, A[1]);
point R(N, A[N]);
vector<point> hull = {L};
for (int i = 2; i <= N; i++) {
point cur(i, A[i]);
if (i != N && !ccw(L, cur, R)) {
continue;
}
while ((int)hull.size() >= 2 && !ccw(hull.end()[-2], hull.back(), cur)) {
hull.pop_back();
}
hull.push_back(cur);
}
return hull;
}
void just_do_it() {
int N, M;
cin >> N >> M;
for (int i = 1; i <= N; i++) {
cin >> A[i];
}
for (int i = 1; i <= M; i++) {
cin >> B[i];
}
vector<point> hullA = build(A, N);
vector<point> hullB = build(B, M);
int szA = hullA.size();
int szB = hullB.size();
int ptA = 0;
int ptB = 0;
int cx = 1;
int cy = 1;
long long res = 0;
while (ptA < szA - 1 || ptB < szB - 1) {
if (ptA < szA - 1 && (ptB == szB - 1 || ((hullA[ptA + 1] - hullA[ptA]) ^ (hullB[ptB + 1] - hullB[ptB])) > 0)) {
ptA++;
res += (hullA[ptA].x - cx) * B[cy];
cx = hullA[ptA].x;
}
else {
ptB++;
res += (hullB[ptB].x - cy) * A[cx];
cy = hullB[ptB].x;
}
}
cout << res;
}
