#include<bits/stdc++.h>
using namespace std;
// define
//bool M1;
//#define execute cerr << " Time: " << fixed << setprecision(6) << (1.0 * clock() / CLOCKS_PER_SEC) << "s\n";
//#define memory cerr << abs(&M2 - &M1)/1024.0/1024 << " MB" << "\n"
#define ll long long
#define ii pair <ll , ll>
#define iii pair <int , ii>
#define se second
#define fi first
#define all(v) (v).begin() , (v).end()
#define Unique(v) sort(all(v)) , v.resize(unique(all(v)) - v.begin())
#define bit(x,i) (((x) >> (i)) & 1LL)
#define flip(x,i) ((x) ^ (1LL << (i)))
#define ms(d,x) memset(d , x , sizeof(d))
#define exist __exist
#define ends __ends
#define visit visited
#define left __left
#define right __right
#define prev __prev
#define next __next
#define sitingfake 1
#define orz 1
//constant
const long long mod = 1e9 + 7;
const long long linf = 4557430888798830399LL;
const long long nlinf = -4485090715960753727LL;
const int inf = 1061109567;
const int ninf = -1044266559;
const int dx[] = {0 , -1 , 0 , 1};
const int dy[] = {-1 , 0 , 1 , 0};
template<typename T> bool maximize(T &a, const T &b)
{
if(a < b) {a = b; return 1;}
return 0;
}
template<typename T> bool minimize(T &a, const T &b)
{
if(a > b) {a = b; return 1;}
return 0;
}
void Plus(ll & a ,ll b)
{
b %= mod;
a += b;
if(a < 0) a += mod;
a %= mod;
return;
}
void Mul(ll & a, ll b)
{
(a *= (b % mod)) %= mod;
return;
}
//code
const int maxn = 1e5 + 7;
int a[maxn] , b[maxn];
int n , m;
namespace sub1
{
ll dp[1002][1002];
void solve()
{
ms(dp , 0x3f);
dp[1][1] = 0;
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= m; j++)
{
if(ii(i , j) == ii(1 , 1)) continue;
dp[i][j] = linf;
if(i) dp[i][j] = min(dp[i][j] , dp[i - 1][j] + 1ll * b[j]);
if(j) dp[i][j] = min(dp[i][j] , dp[i][j - 1] + 1ll * a[i]);
}
}
cout << dp[n][m];
}
}
namespace sub2
{
ll dp[1005][1005];
bool approve() {
for(int i = 1; i <= n; i++) if(a[i] > 1000) return 0;
for(int i = 1; i <= m; i++) if(b[i] > 1000) return 0;
return 1;
}
void solve()
{
vector <int> new_a , new_b;
int Min = inf;
for(int i = 1; i <= n; i++)
{
if(minimize(Min , a[i])) new_a.push_back(i);
}
Min = inf;
for(int i = n; i >= 1; i--)
{
if(minimize(Min , a[i])) new_a.push_back(i);
}
Min = inf;
for(int i = 1; i <= m; i++)
{
if(minimize(Min , b[i])) new_b.push_back(i);
}
Min = inf;
for(int i = m; i >= 1; i--)
{
if(minimize(Min , b[i])) new_b.push_back(i);
}
Unique(new_a);
Unique(new_b);
n = new_a.size();
m = new_b.size();
ms(dp , 0x3f);
dp[1][1] = 0;
for(int i = 1; i <= n; i++)
{
for(int j = 1; j <= m; j++)
{
if(ii(i , j) == ii(1 , 1)) continue;
dp[i][j] = linf;
if(i) dp[i][j] = min(dp[i][j] , dp[i - 1][j] + 1ll * (new_a[i - 1] - new_a[i - 2]) * b[j]);
if(j) dp[i][j] = min(dp[i][j] , dp[i][j - 1] + 1ll * (new_b[i - 1] - new_b[i - 2]) * a[i]);
}
}
cout << dp[n][m];
}
}
namespace sub3
{
ll ccw(ii a, ii b , ii c)
{
return (c.se - a.se) * (b.fi - a.fi) - (c.fi - a.fi) * (b.se - a.se);
}
bool cmp(ii &a1 , ii &a2 , ii &b1 , ii &b2)
{
ll d_Xa = a2.fi - a1.fi;
ll d_Ya = a2.se - a1.se;
ll d_Xb = b2.fi - b1.fi;
ll d_Yb = b2.se - b1.se;
// ya / xa <= yb / xb
return d_Ya * d_Xb <= d_Yb * d_Xa;
}
void debug(vector <ii> p)
{
cout << endl;
for(ii it : p) cout << it.fi << " " << it.se << endl;
cout << endl;
}
void solve()
{
vector <ii> HullA , HullB;
HullA.push_back({n , a[n]});
HullA.push_back({n - 1 , a[n - 1]});
for(int i = n - 2; i >= 1; i--)
{
while(HullA.size() >= 2 && ccw(HullA[HullA.size() - 2] , HullA.back() , ii(i , a[i])) >= 0)
{
HullA.pop_back();
}
HullA.push_back({i , a[i]});
}
reverse(all(HullA));
HullB.push_back({m , b[m]});
HullB.push_back({m - 1 , b[m - 1]});
for(int i = m - 2; i >= 1; i--)
{
while(HullB.size() >= 2 && ccw(HullB[HullB.size() - 2] , HullB.back() , ii(i , b[i])) >= 0)
{
HullB.pop_back();
}
HullB.push_back({i , b[i]});
}
reverse(all(HullB));
//
// debug(HullA);
// debug(HullB);
int itL = 1 , itR = 1;
n = HullA.size();
m = HullB.size();
ll ans = 0;
while(itL < n && itR < m) {
if(cmp(HullA[itL - 1] , HullA[itL] , HullB[itR - 1] , HullB[itR]))
{
ans += HullB[itR - 1].se * (HullA[itL].fi - HullA[itL - 1].fi);
++itL;
}
else
{
ans += HullA[itL - 1].se * (HullB[itR].fi - HullB[itR - 1].fi);
++itR;
}
}
//cout << itL << " " << itR << " " << ans << endl;
for(int i = itL; i < n; i++)
{
ans += (HullA[i].fi - HullA[i - 1].fi) * HullB[m - 1].se;
}
for(int i = itR; i < m; i++)
{
ans += (HullB[i].fi - HullB[i - 1].fi) * HullA[n - 1].se;
}
cout << ans;
}
}
void solve(void)
{
cin >> n >> m;
for(int i = 1; i <= n; i++) cin >> a[i];
for(int i = 1; i <= m; i++) cin >> b[i];
if(n <= 1000 && m <= 1000) return sub1 :: solve();
if(sub2 :: approve()) return sub2 :: solve();
return sub3 :: solve();
}
/**
**/
//bool M2;
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define task ""
if(fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) solve();
// execute;
// memory;
}
