import sys
from math import sqrt, pi, sin
inp = lambda : sys.stdin.readline()[:-1]
mii = lambda x = " ": [*map(int,inp().split(x))]
mfi = lambda x = " ": [*map(float,inp().split(x))]
ii = lambda : int(inp())
while 1:
n = ii()
if n == 0:
break
l = sorted(mii())
ans = 111111111111111111
for i in range(1, n):
ans = min(ans, l[i] - l[i - 1])
print(ans)