#!/usr/bin/env python3
import sys

def search(nums, maximum):
    # idx to consider
    i = 0
    while len(nums) > 1:
        # count just that digit in the string (rest is garbage)
        counts = [0, 0]
        for n in nums:
            counts[int(n[i])] += 1

        # filter the list down to most or least common
        is_zero = lambda x: x[i] == "0"
        is_one = lambda x: x[i] == "1"
        if (maximum and counts[0] > counts[1]) or (not maximum and counts[0] <= counts[1]):
            nums = list(filter(is_zero, nums))
        else:
            nums = list(filter(is_one, nums))
        i+=1

    return nums[0]

# We need multiple iterations on this one -- save to mem
if __name__ == '__main__':
    nums = []
    for l in sys.stdin:
        nums.append(l.strip())

    oxygen = int(search(nums, maximum=True), 2)
    co2 = int(search(nums, maximum=False), 2)

    print(oxygen * co2)