#!/usr/bin/env python3


def find(is_lowest):
    lines = (x.strip() for x in open("input.txt"))
    for bit in range(12):
        zeros = []
        ones = []
        for line in lines:
            zeros.append(line) if line[bit] == '0' else ones.append(line)
        lines = zeros if (len(zeros) > len(ones)) != is_lowest else ones
        if len(lines) <= 1:
            break
    return lines[0]


gamma = int(''.join(find(True)), 2)
epsilon = int(''.join(find(False)), 2)

print(gamma * epsilon)