import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N,*X = map(int,read().split())

X = sorted(set(X))

if len(X) == 1:
    print(0)
else:
    x = min(y - x for x,y in zip(X,X[1:]))
    print(x)