#include<bits/stdc++.h>
using namespace std;
int h,w;
long long a[2][100005];
long long l[2][100005], r[2][100005];
set< pair<double, pair<int,int> > > st;
double calc(int id, int y) {
int x = l[id][y];
return ((double)(a[id][y]-a[id][x])) / (y-x);
}
int main() {
ios::sync_with_stdio(false);
cin >> h >> w;
l[0][h+1] = h;
for(int i=1; i<=h; i++) {
cin >> a[0][i];
l[0][i] = i-1; r[0][i] = i+1;
}
l[1][w+1] = w;
for(int i=1; i<=w; i++) {
cin >> a[1][i];
l[1][i] = i-1; r[1][i] = i+1;
}
for(int i=2; i<=h; i++) {
st.insert({calc(0, i), {0, i} });
}
for(int i=2; i<=w; i++) {
st.insert({{calc(1, i), {1, i} }});
}
long long ans = 0;
for(int i=0; i<h+w-2; i++) {
int id = (*prev(st.end())).second.first;
int y = (*prev(st.end())).second.second;
if(id==0) {
if(r[0][y] > h) {
ans += (a[1][l[1][w+1]] * (y - l[0][y]));
} else {
st.erase({calc(0, r[0][y]), {0, r[0][y]} });
}
} else {
if(r[1][y] > w) {
ans += (a[0][l[0][h+1]] * (y - l[1][y]));
} else {
st.erase({calc(1, r[1][y]), {1, r[1][y]} });
}
}
st.erase(prev(st.end()));
l[id][r[id][y]] = l[id][y];
r[id][l[id][y]] = r[id][y];
if(r[id][y] <= (id==0?h:w) && l[id][y] > 0) {
st.insert({calc(id, r[id][y]), {id, r[id][y]} });
}
}
cout << ans << "\n";
}
