#include<bits/stdc++.h>
#define fi first
#define se second
#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)
#define compact(v) v.erase(unique(all(v)), end(v))
#define sz(v) (int)(v).size()
#define endl "\n"
#define dbg(x) "[" #x " = " << (x) << "]"
using namespace std;
template<class T> bool minimize(T& a, T b){
if(a > b) return a = b, true;
return false;
}
template<class T> bool maximize(T& a, T b){
if(a < b) return a = b, true;
return false;
}
typedef long long ll;
void fastIO(){
ios_base::sync_with_stdio(NULL); cin.tie(0);
#ifdef LOCAL
freopen("task.INP", "r", stdin);
freopen("task.OUT", "w", stdout);
#endif
}
struct point{
ll x, y;
point() : x(0), y(0) {}
point(ll x, ll y) : x(x), y(y) {}
};
ll cross(point a, point b){
return a.x*b.y - a.y*b.x;
}
void vectorize(point& a, point b){
a.x -= b.x;
a.y -= b.y;
}
ll cross_product(point a, point b, point c){
vectorize(b, a);
vectorize(c, a);
return cross(b, c);
}
void lower_hull_construction(vector<point>& a){
vector<point> hull;
for(auto e : a){
while(sz(hull) > 1 && cross_product(hull[sz(hull)-2], e, hull.back()) >= 0) hull.pop_back();
hull.push_back(e);
}
swap(a, hull);
return;
}
signed main(){
fastIO();
int H, W; cin >> H >> W;
vector<point> a, b;
for(int i = 1; i <= H; i++){
int x; cin >> x;
a.push_back(point(i, x));
}
for(int i = 1; i <= W; i++){
int x; cin >> x;
b.push_back(point(i, x));
}
lower_hull_construction(a);
lower_hull_construction(b);
int i = 0, j = 0;
ll answer = 0;
while(i < sz(a) - 1 || j < sz(b) - 1){
if(i + 1 == sz(a)){
answer += 1LL*(b[j+1].x - b[j].x)*a[i].y;
j++;
continue;
}
if(j + 1 == sz(b)){
answer += 1LL*(a[i+1].x - a[i].x)*b[j].y;
i++;
continue;
}
ll A = 1LL*(a[i].y - a[i+1].y)*(b[j+1].x - b[j].x);
ll B = 1LL*(b[j].y - b[j+1].y)*(a[i+1].x - a[i].x);
if(A > B){
answer += 1LL*(a[i+1].x - a[i].x)*b[j].y;
i++;
}
else{
answer += 1LL*(b[j+1].x - b[j].x)*a[i].y;
j++;
}
}
cout << answer;
}
