rt

#include<bits/stdc++.h>
using namespace std;
#define int long long

inline int read()
{
	char ch=getchar();
	int f=1,x=0;
	while(!isdigit(ch)){if(ch=='-')f=-f;ch=getchar();}
	while(isdigit(ch))x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
	return x*f;
}

inline void _write(int x)
{
	if(x>9)_write(x/10);
	putchar((x%10)+'0');
}

inline void write(int x,short f=0)
{
	if(x<0)putchar('-'),x=-x;
	_write(x);
	if(f!=0)putchar(char(f));
}

int n,a[1000005],mxx[1000005];

signed main()
{
	int ans=-9e18;
	n=read();
	for(int i=1;i<=n;i++)
		a[i]=read();
	mxx[n]=a[n];
	for(int i=n-1;i>=1;i--)
		mxx[i]=max(a[i],mxx[i+1]);
	for(int i=1;i<=n;i++)
		ans=max(ans,mxx[i+1]-a[i]);
	write(ans);
	return 0;
}