#include "bits/stdc++.h"
using namespace std;
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define ar array
#define all(v) begin(v), end(v)
#define sz(v) static_cast<int>(v.size())
typedef vector<int> vi;
typedef long long ll;
struct Point {
ll x, y;
bool operator<(const Point& p) const {
return x < p.x || (x == p.x && y < p.y);
}
bool operator==(const Point& p) const { return (x == p.x && y == p.y); }
Point operator-(const Point& p) const { return {x - p.x, y - p.y}; }
friend ll abs(const Point& a) { return a.x * a.x + a.y * a.y; }
friend ll cross(const Point& a, const Point& b) {
return a.x * b.y - a.y * b.x;
}
friend ll cross(const Point& p, const Point& a, const Point& b) {
return cross(a - p, b - p);
}
};
vector<Point> getHull(vi a) {
vector<Point> p;
F0R(i, sz(a)) {
Point now = {i, a[i]};
while (sz(p) > 1 && cross(p[sz(p) - 2], now, p[sz(p) - 1]) >= 0)
p.pop_back();
p.push_back(now);
}
return p;
}
int32_t main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
cin.exceptions(cin.failbit);
int n, m;
cin >> n >> m;
vi a(n), b(m);
F0R(i, n) cin >> a[i];
F0R(j, m) cin >> b[j];
auto pa = getHull(a), pb = getHull(b);
int i = 0, j = 0;
ll ans = 0;
while (i + 1 < sz(pa) || j + 1 < sz(pb)) {
bool c;
if (i + 1 == sz(pa))
c = 0;
else if (j + 1 == sz(pb))
c = 1;
else
c = (pa[i + 1].y - pa[i].y) * (pb[j + 1].x - pb[j].x) <=
(pb[j + 1].y - pb[j].y) * (pa[i + 1].x - pa[i].x);
if (c)
ans += (pa[i + 1].x - pa[i].x) * pb[j].y, i++;
else
ans += (pb[j + 1].x - pb[j].x) * pa[i].y, j++;
}
cout << ans << endl;
}
