tmp = input()
X = sorted([int(i) for i in input().strip().split(' ')])

tmp = -1
for i in range(len(X) - 1):
  if X[i] != X[i+1]:
    if tmp == -1 or tmp > X[i+1] - X[i]:
      tmp = X[i+1] - X[i]

print(str(tmp) if tmp > -1 else 0)