1419. Minimum Number of Frogs Croaking

https://leetcode.com/problems/minimum-number-of-frogs-croaking/

class Solution:
    def minNumberOfFrogs(self, croakOfFrogs: str) -> int:
        n = len(croakOfFrogs)
        if n % 5 != 0:
            return -1
        c= 0
        r=0
        o = 0
        a=0
        k = 0
        in_use = 0
        res = 0
  
        for val in croakOfFrogs:
            if val == "c":
                c+=1
                in_use+=1
            elif val == "r":
                r+=1
            elif val == "o":
                o+=1
            elif val == "a":
                a+=1
            elif val == "k":
                k+=1
                in_use-=1
            if c < r or r < o or o < a or a < k:
                return -1
            res = max(res,in_use)
        if c==r==o==a==k and in_use ==0:
            return res
        return -1