class Solution:
def complexNumberMultiply(self, a: str, b: str) -> str:
a_r, a_v = a.split('+')
a_r, a_v = int(a_r), int(a_v[:-1]) #a的实部和虚部
b_r, b_v = b.split('+')
b_r, b_v = int(b_r), int(b_v[:-1])
#格式化输出
return str(a_r*b_r + -a_v*b_v) + '+' + str(a_v*b_r + b_v*a_r) + 'i'
