#include //ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); //clock_t start=clock();clock_t end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC< pii; typedef pair ppii; typedef pair pipi; typedef pair pll; typedef pair ppll; typedef pair plpl; typedef pair pippi; typedef tuple tl; typedef pair pdd; typedef vector> mat; ll mod=1000000007; ll mod2=998244353; ll mod3=1000003; ll mod4=998244853; ll mod5=1000000009; ll inf=1LL<<61; int iinf=1<<30; double pi=3.14159265358979323846; double pi2=pi/2.0; double eps=1e-8; #define rep(i,m,n) for(int i=m;i=m;i--) #define srep(itr,st) for(auto itr=st.begin();itr!=st.end();itr++) #define mrep(itr,mp) for(auto& itr:mp) #define Max(a,b) a=max(a,b) #define Min(a,b) a=min(a,b) //#define endl "\n" int dh[4]={1,0,-1,0}; int dw[4]={0,1,0,-1}; int ddh[8]={-1,-1,-1,0,0,1,1,1}; int ddw[8]={-1,0,1,-1,1,-1,0,1}; struct custom_hash { static uint64_t splitmix64(uint64_t x) { // http://xorshift.di.unimi.it/splitmix64.c x += 0x9e3779b97f4a7c15; x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9; x = (x ^ (x >> 27)) * 0x94d049bb133111eb; return x ^ (x >> 31); } size_t operator()(uint64_t x) const { static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count(); return splitmix64(x + FIXED_RANDOM); } }; #define umh unordered_map ll gcd(ll a,ll b){ if(a<0)a=-a; if(b<0)b=-b; if(a0){ if(k&1)ret*=now; now*=now; k/=2; } return ret; } ll beki(ll n,ll k,ll md){ ll ret=1; ll now=n; now%=md; while(k>0){ if(k%2==1){ ret*=now; ret%=md; } now*=now; now%=md; k/=2; } return ret; } ll gyaku(ll n,ll md){ return beki(n,md-2,md); } ll popcount(ll n){ ll ret=0; ll u=n; while(u>0){ ret+=u%2; u/=2; } return ret; } int main(){ ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); ll n,m;cin>>n>>m; ll a[n],b[m]; rep(i,0,n)cin>>a[i]; rep(i,0,m)cin>>b[i]; ll gb[n][m]; ll g[n][m]; rep(i,0,n){ rep(j,0,m){ g[i][j]=gcd(a[i],b[j]); //gb[i][j]=gyaku(b[j]/g[i][j],mod); } } ll gg=gyaku(2,mod); ll ans=0; rep(i,0,n){ rep(j,0,m){ ll c=g[i][j]; ll na=a[i]/c,nb=b[j]/c; ll sum=(nb-1)*gg%mod; sum%=mod; (sum*=(na-1+mod))%=mod; //cout<