#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#define dbg(...) printf(__VA_ARGS__);
#define getchar_unlocked getchar
#else
#define dbg(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 1023456789123456789
#define all(x) x.begin(), x.end()
#define disc(x) sort(all(x));x.resize(unique(all(x))-x.begin());
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;
mt19937 rng(time(0));
#define mod 1000000007
inline int add(int a,int b){
int r=a+b;
while(r>=mod)r-=mod;
while(r<0)r+=mod;
return r;
}
inline int mult(int a,int b){
return (int)(((ll)(a*b))%mod);
}
inline int rd(){
int x=0;
char ch=getchar_unlocked();
while(!(ch&16))ch=getchar();//keep reading while current character is whitespace
while(ch&16){//this will break when ‘\n’ or ‘ ‘ is encountered
x=(x<<3)+(x<<1)+(ch&15);
ch=getchar_unlocked();
}
return x;
}
#define maxn 1005
int h,w,a[maxn],pa[maxn],sa[maxn],b[maxn],pb[maxn],sb[maxn];
ll memo[maxn][maxn];
vector<pll> aa,bb;
ll dp(int i,int j){
if(i==h&&j==w)return 0;
if(i>h||j>w)return LINF;
if(memo[i][j]!=-1)return memo[i][j];
return memo[i][j]=min(dp(i+1,j)+bb[j].fi*(aa[i+1].se-aa[i].se),dp(i,j+1)+aa[i].fi*(bb[j+1].se-bb[j].se));
}
int main(){
sf("%d%d",&h,&w);
for(int i=1;i<=h;++i)sf("%d",&a[i]);
for(int i=1;i<=w;++i)sf("%d",&b[i]);
pa[0]=sa[h+1]=pb[0]=sb[w+1]=INF;
for(int i=1;i<=h;++i)pa[i]=min(pa[i-1],a[i]);
for(int i=h;i>=1;--i)sa[i]=min(sa[i+1],a[i]);
for(int i=1;i<=w;++i)pb[i]=min(pb[i-1],b[i]);
for(int i=w;i>=1;--i)sb[i]=min(sb[i+1],b[i]);
for(int i=1;i<=h;++i)if(pa[i-1]>a[i]||a[i]<sa[i+1])aa.pb({a[i],i});
for(int i=1;i<=w;++i)if(pb[i-1]>b[i]||b[i]<sb[i+1])bb.pb({b[i],i});
h=aa.size()-1,w=bb.size()-1;
aa.pb({INF,INF});bb.pb({INF,INF});
memset(memo,-1,sizeof memo);
/*
for(int i=0;i<=h;++i){
for(int j=0;j<=w;++j){
pf("%3lld ",dp(i,j));
}
pf("\n");
}
*/
pf("%lld\n",dp(0,0));
}
