class Solution:
    def minNumberOfFrogs(self, s: str) -> int:
        d = [float("inf"),0,0,0,0,0]
        dic = {"c":1, "r":2, "o":3,"a":4,"k":5}
        ans = 0
        for c in s:
            d[dic[c]-1] -= 1
            d[dic[c]] += 1
            if min(d) < 0:
                return -1
            ans = max(ans,sum(d[1:5]))
        return ans if sum(d[1:5]) == 0 else -1