680 B | 680 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
sys.setrecursionlimit(10**7)
BLANK = " "
#inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
n = ii()
l = mii()
s = l[0]
ans = 0
for i in range(1, n):
crt = l[i]
prev = l[i - 1]
if prev >= crt:
s = crt
else:
ans = max(ans, crt - s)
p(ans)
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()