CCF 2017-12-1最小差值 python

n=input()
n=eval(n)
a=input().split(' ')
a=[eval(item) for item in a]

min=abs(a[0]-a[1])

for i in range(0,n-1):
    for j in range(i+1,n):
        if abs(a[i]-a[j])<min:
                min=abs(a[i]-a[j])

print(min)