/*input
4 6
454863204 543362989 866044086 813602010
71574269 17945210 688720933 392135202 38174709 168241720
*/
#include<bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<long long,null_type,less_equal<long long>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
#pragma GCC optimize("Ofast")
//#pragma GCC target("avx2")
//order_of_key #of elements less than x
// find_by_order kth element
using ll=long long;
using ld=long double;
using pii=pair<int,int>;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()),c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
const ll maxn=2e5+5;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int INF=0x3f3f3f3f;
const ll MOD=1e9+7;
const ld PI=acos(-1);
const ld eps=1e-6;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
out<<P.f<<' '<<P.s;
return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
REP(i,sz(V)) out<<V[i]<<((i!=sz(V)-1)?" ":"");
return out;
}
ll mult(ll a,ll b){
return a*b%MOD;
}
ll mypow(ll a,ll b){
a%=MOD;
if(a==0) return 0;
if(b<=0) return 1;
ll res=1LL;
while(b){
if(b&1) res=(res*a)%MOD;
a=(a*a)%MOD;
b>>=1;
}
return res;
}
int pf[maxn];
int a[maxn],b[maxn];
ll dp[3005][3005];
int main(){
int n,m;
cin>>n>>m;
pf[0]=INF;
REP1(i,n) cin>>a[i],pf[i]=min(pf[i-1],a[i]);
int sf=INF;
vector<int> v;
for(int i=n;i>=1;i--){
if(a[i]<sf or a[i]<pf[i-1]){
v.pb(i);
}
}
pf[0]=INF;
REP1(i,m) cin>>b[i],pf[i]=min(pf[i-1],b[i]);
sf=INF;
vector<int> v2;
for(int i=m;i>=1;i--){
if(b[i]<sf or b[i]<pf[i-1]){
v2.pb(i);
}
}
reverse(ALL(v)),reverse(ALL(v2));
REP(i,sz(v)){
REP(j,sz(v2)){
if(!i and !j){
dp[i][j]=0;
continue;
}
dp[i][j]=INF64;
if(i) MNTO(dp[i][j],dp[i-1][j]+1LL*(v[i]-v[i-1])*b[v2[j]]);
if(j) MNTO(dp[i][j],dp[i][j-1]+1LL*(v2[j]-v2[j-1])*a[v[i]]);
}
}
cout<<dp[sz(v)-1][sz(v2)-1];
}
