package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

const entryBits = 12
//const entryBits = 5

func nthBit(f int, i int) int {
	a := entryBits - i - 1
	return f & (1 << a) >> a
}

type NumberList []int

func (n NumberList) CountBits(index int) (ones int, zeroes int) {
	for _, num := range n {
		if nthBit(num, index) == 1 {
			ones++
		} else {
			zeroes++
		}
	}
	return
}

func (n NumberList) Filter(index int, bit int) NumberList {
	var res NumberList
	for _, num := range n {
		if nthBit(num, index) == bit {
			res = append(res, num)
		}
	}
	return res
}

func main() {
	var numbers NumberList

	s := bufio.NewScanner(os.Stdin)
	for s.Scan() {
		value, _ := strconv.ParseInt(s.Text(), 2, 64)
		numbers = append(numbers, int(value))
	}

	oxygenNumbers := numbers
	for i := 0; i < entryBits; i++ {
		ones, zeroes := oxygenNumbers.CountBits(i)

		var bit int
		if ones >= zeroes {
			bit = 1
		} else {
			bit = 0
		}

		//fmt.Println(i, bit, zeroes, ones, len(oxygenNumbers))
		oxygenNumbers = oxygenNumbers.Filter(i, bit)
		if len(oxygenNumbers) == 1 {
			break
		}
	}
	oxygen := oxygenNumbers[0]

	co2Numbers := numbers
	for i := 0; i < entryBits; i++ {
		ones, zeroes := co2Numbers.CountBits(i)

		var bit int
		if ones < zeroes {
			bit = 1
		} else {
			bit = 0
		}

		//fmt.Println(i, bit, zeroes, ones, len(co2Numbers))
		co2Numbers = co2Numbers.Filter(i, bit)
		if len(co2Numbers) == 1 {
			break
		}
	}
	co2 := co2Numbers[0]

	fmt.Println(oxygen * co2)
}