Python Greedy Solution
\nclass Solution:\n    def minDeletionSize(self, strs: List[str]) -> int:\n        m = len(strs)\n        n = len(strs[0])\n\n        cur = ["" for i in range(m
```\nclass Solution:\n    def minDeletionSize(self, strs: List[str]) -> int:\n        m = len(strs)\n        n = len(strs[0])\n\n        cur = ["" for i in range(m)]\n        res = 0\n\n        for i in range(n):\n            temp = [x for x in cur]\n            valid = True\n            \n            temp[0] += strs[0][i]\n            for j in range(1,m):\n                temp[j] += strs[j][i]\n                if temp[j] < temp[j-1]:\n                    res += 1\n                    valid = False\n                    break\n            \n            if valid:cur = temp\n        \n        return res\n```
['Python3']