遍历所有四位数

for num in range(1000, 10000):

s = str(num)

if s[0] != s[1]:
    continue

if s[2] != s[3]:
    continue

if s[0] == s[2]:
    continue

sqr = int(num ** 0.5)
if sqr * sqr == num:
    print(num)
    break