[4,7,2,8,3]import sys
import math

inputs=input().split(" ")

temperaturelist3=inputs[0]
temperaturelist2=temperaturelist3.replace("[","")
temperaturelist1=temperaturelist2.replace("]","")
temperaturelist0=temperaturelist1.split(",")

temperaturelist=list(map(int,(temperaturelist0)))

drop=0
highest=0

for i in temperaturelist:
    if i>highest:
        highest=i

    if i<highest:
        if (highest-i)>=drop:
            drop=highest-i
        if (highest-i)<drop:
            drop=drop
print(drop)