package main

func MaximalRectangle(matrix [][]byte) (ans int) {
	var heights []int
	for _, v1 := range matrix {
		for i, v2 := range v1 {
			n := int(v2 - 48)
			if n == 0 {
				heights[i] = 0
			} else {
				heights[i] += n
			}
		}
		ans = getMax(Largest(heights), ans)
	}
	return
}

func getMax(n1, n2 int) int {
	if n1 > n2 {
		return n1
	}
	return n2
}