592. Fraction Addition and Subtraction

from math import gcd
class Solution:
    def fractionAddition(self, esp: str) -> str:
        n=len(esp)
        esp=esp.replace('+',' +').replace('-',' -')
        nums=esp.split()

        n,d=0,1
        for num in nums:
            a,b=num.split('/')
            a,b=int(a),int(b)
            n,d=n*b+a*d,d*b
            g=gcd(n,d)
            n,d=n//g,d//g
        return "{}/{}".format(n,d)