#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = (int)1e5 + 12, MOD = 998244353;
struct vec{
ll x, y;
};
bool check(vec a, vec b) {
return (a.x * b.y - b.x * a.y >= 0);
}
vector<int> get(int n, int a[]) {
vector<int> st;
for(int i = n; i >= 1; i--) {
while((int)st.size() >= 2) {
int j = st.back(), k = st[(int)st.size() - 2];
if((a[j] - a[i]) * 1ll * (k - j) - (a[k] - a[j]) * 1ll * (j - i) > 0) {
st.pop_back();
} else break;
}
st.push_back(i);
}
reverse(st.begin(), st.end());
return st;
}
int n, m, a[N], b[N];
void test() {
cin >> n >> m;
for(int i = 1; i <= n; i++) {
cin >> a[i];
}
for(int i = 1; i <= m; i++) {
cin >> b[i];
}
vector<int> x = get(n, a), y = get(m, b);
n = (int)x.size(), m = (int)y.size();
int px = 0, py = 0;
ll res = 0;
while(px < n - 1 || py < m - 1) {
if(px == n - 1) {
res += (y[py + 1] - y[py]) * 1ll * a[x[px]];
py++;
} else if(py == m - 1) {
res += (x[px + 1] - x[px]) * 1ll * b[y[py]];
px++;
} else {
vec A = {a[x[px + 1]] - a[x[px]], x[px + 1] - x[px]};
vec B = {b[y[py + 1]] - b[y[py]], y[py + 1] - y[py]};
if(!check(A, B)) {
res += (x[px + 1] - x[px]) * 1ll * b[y[py]];
px++;
} else {
res += (y[py + 1] - y[py]) * 1ll * a[x[px]];
py++;
}
}
}
cout << res << '\n';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int t = 1;
// cin >> t;
while(t--) {
test();
}
}
