#include<stdio.h>const unsigned long long inf=(1<<63)-1+(1<<63);typedef unsigned long long ll;int n,m;ll a[20];ll ans;ll gcd(ll a,ll b){ if(a<b) a=a^b,b=a^b,a=a^b; if(!b) return a; while(b) { ll t=a; a=b; b=t%b; } return a;}ll lcm(ll a,ll b){ ll tmp=a/gcd(a,b); if(tmp>(inf/b)) return inf; return tmp*b;}void dfs(ll flag,int x,ll num,ll b){ if(flag&1) ans+=b/num; else ans-=b/num; for(int i=x+1;i<=n;i++) { dfs(flag+1,i,lcm(num,a[i]),b); } return;}ll solve(ll l,ll r){ int i; ll result=0; ans=0; for(i=1;i<=n;i++) dfs(1,i,a[i],l); result+=ans; ans=0; for(i=1;i<=n;i++) dfs(1,i,a[i],r); result=ans-result; for(i=1;i<=n;i++) { a[i]=lcm(a[i],a[n+1]); } ans=0; for(i=1;i<=n;i++) dfs(1,i,a[i],l); result+=ans; ans=0; for(i=1;i<=n;i++) dfs(1,i,a[i],r); result-=ans; return result;}int main(){ int i; ll l,r; scanf("%d %d %llu %llu",&n,&m,&l,&r); while(!(n==0 && m==0 && l==0 && r==0)) { for(i=1;i<=n;i++) { scanf("%llu",&a[i]); } a[n+1]=1; ll tmp; for(i=1;i<=m;i++) { scanf("%llu",&tmp); a[n+1]=lcm(a[n+1],tmp); } ll result=solve(l-1,r); printf("%llun",result); scanf("%d %d %llu %llu",&n,&m,&l,&r); } return 0;}
