#include <iostream>
#include <sstream>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <cstring>
#include <bitset>
#include <functional>
#include <random>
#define REP(i,a,n) for(int i=a;i<=n;++i)
#define PER(i,a,n) for(int i=n;i>=a;--i)
#define hr putchar(10)
#define pb push_back
#define lc (o<<1)
#define rc (lc|1)
#define mid ((l+r)>>1)
#define ls lc,l,mid
#define rs rc,mid+1,r
#define x first
#define y second
#define io std::ios::sync_with_stdio(false)
#define endl '\n'
#define DB(a) ({REP(__i,1,n) cout<<a[__i]<<' ';hr;})
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int P = 1e9+7, INF = 0x3f3f3f3f;
ll gcd(ll a,ll b) {return b?gcd(b,a%b):a;}
ll qpow(ll a,ll n) {ll r=1%P;for (a%=P;n;a=a*a%P,n>>=1)if(n&1)r=r*a%P;return r;}
ll inv(ll x){return x<=1?1:inv(P%x)*(P-P/x)%P;}
inline int rd() {int x=0;char p=getchar();while(p<'0'||p>'9')p=getchar();while(p>='0'&&p<='9')x=x*10+p-'0',p=getchar();return x;}
//head



const int N = 1e6+50;
int n,m,a[N],b[N];
int sum[N];

ll solve(int *a, int n) {
	REP(i,1,n) sum[i]=(sum[i-1]+a[i])%P;
	ll ans = 0;
	REP(i,1,n) ans=(ans+(ll)(n-i)*a[i]-(sum[n]-sum[i]))%P;
	if (ans<0) ans += P;
	return ans;
}
int main() {
	scanf("%d%d",&n,&m);
	REP(i,1,n) scanf("%d",a+i);
	REP(i,1,m) scanf("%d",b+i);
	printf("%lld\n",solve(a,n)*solve(b,m)%P);
}







#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
using ll=long long;

int main() {
    int N,K;cin>>N>>K;
    vector<int> p(N);
    for (int i = 0; i < N; i++){
        cin>>p[i];
    }
    int ans=0;
    for (int i = 0; i < K; i++){
        ans+=p[i]+1;
    }
    int sum=ans;
    for (int i = 0; i < N-K; i++){
        sum=sum-p[i]+p[i+K];
        ans=max(ans,sum);
    }
    cout<<ans/2;
    if(ans%2!=0)cout<<".5"<<endl;
}