arr = sorted(eval(input()))
maxnum = 0
if len(arr) < 2:
    print('0')
else:
    for i in range(len(arr) - 1):
        if arr[i + 1] - arr[i] > maxnum:
            maxnum = arr[i + 1] - arr[i]
    print(maxnum)

fcbfde48e83ac47d077e2c9447733c2912a80dde
<mask token>

<mask token>
if len(arr) < 2:
    print('0')
else:
    for i in range(len(arr) - 1):
        if arr[i + 1] - arr[i] > maxnum:
            maxnum = arr[i + 1] - arr[i]
    print(maxnum)

arr = sorted(eval(input()))
maxnum = 0
if len(arr) < 2:
    print('0')
else:
    for i in range(len(arr) - 1):
        if arr[i + 1] - arr[i] > maxnum:
            maxnum = arr[i + 1] - arr[i]
    print(maxnum)
