我的代码拿题目那三个数据样例在洛谷IDE和自己的Python3.8.10跑都正常输出不超时不爆内存，到题目里一提交就RE

PyPy3不会RE但内存炸了……谁来救救我……

strs = []
inp = input().split(" ")
r, c = int(inp[0]), int(inp[1])
for each in range(r):
    strs.append(input())
mx = r-1

def g(i=r-1, same=range(c)):
    global mx
    if i < mx:
        mx = i
    s = strs[i]
    chars = []
    for each in same:
        c = s[each]
        if c in chars:
            continue
        chars.append(c)
        if s.count(c) > 1:
            index = 0
            samesub = []
            for e in same:
                if s[e] == c:
                    samesub.append(e)
            g(i-1, samesub)
g()
print(mx)