#include<bits/stdc++.h>
using namespace std;
long long x,ans,a[1233];
vector<long long>vec;int n;
int main(){
    scanf("%d",&n);
    for (int i=1;i<=n;i++) scanf("%lld",&a[i]);
    sort(a+1,a+n+1,greater<int>());
    scanf("%lld",&x);vec={x};
    for (int i=1;i<n;i++){
        vector<long long>cur=vec;
        for (auto x:vec) if (x>a[i])
            cur.emplace_back(x%a[i]);
        swap(cur,vec);
    }
    for (auto x:vec) ans=max(ans,x%a[n]);
    printf("%lld\n",ans);
    return 0;
}