C++ :

#include<bits/stdc++.h>
using namespace std;
int n;
const int N=1e6+10;
int a[N];
int ans=-1e9; 
int main()
{
//freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);

cin>>n;
for(int i=1;i<=n;i++)	cin>>a[i];
sort(a+1,a+1+n);
for(int i=1;i<=n-1;i++)
{
	ans=max(ans,a[i]-a[i+1]);

}
	
cout<<ans;


return 0;
}