n = int(input())
 
INF = float("inf")
 
nums = []
for _ in range(n):
  nums.append(int(input()))
 
 
minn = INF
res = 0
 
for i, n in enumerate(nums):
  if n < minn:
    minn = n
  elif n > minn:
    res = max(res, n - minn)
 
 
print(res);
 
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