Given an m × n binary matrix filled with 0s and 1s, find the largest rectangle containing only 1s and return its area.

Example 1:

Input:
1 0 1 0 0
1 0 1 1 1
1 1 1 1 1
1 0 0 1 0
Output: 6

Example 2:

Input:
0
Output: 0

Constraints:

• m == matrix.length
• n == matrix[i].length
• 1 ≤ m, n ≤ 200
• matrix[i][j] is '0' or '1'

Input format: m lines, each with n space-separated integers (0 or 1).

Output format: Maximum rectangle area.