include

using namespace std;

int gcd(int a, int b) { if (a == 0) return b; return gcd(b % a, a); } int lcm(int x, int y ) {

if(x==0)
    return 0;
return (x*y)/gcd(x,y);

}

int main() { int n,m; cin>>n>>m; int a[n],b[m];

for(int i=0; i<n; i++)
{
    cin>>a[i];
}
for(int j=0; j<m; j++)
{
    cin>>b[j];
}


int x=a[0];
int y=b[0];

for(int i=0; i<n; i++)
{

     x=lcm(x,a[i]);


}
for(int j=0; j<m; j++)
{
    y=gcd(y,b[j]);
}


//cout<<x<<endl;
//cout<<y<<endl;

//count the multiples of lcm of a that divides gcd of b
int k=1;
int count=0;
int num=x;
while(x<=y)
{

    if(y%(x)==0) count++;

    k++;
    x=num*k;
}

cout<