1
def get(a):
2
    res = a[1] - a[0]
3
    for i in range(2, len(a)):
4
        res = max(res, a[i] - a[i - 1])
5
    return res
6
 
7
 
8
n = int(input())
9
a = [int(x) for x in input().split()]
10
 
11
ans = []
12
 
13
for i in range(1, n - 1):
14
    b = []
15
    for j in range(n):
16
        if j != i:
17
            b.append(a[j])
18
    
19
    ans.append(get(b))
20
    
21
print(min(ans))