#include <stdio.h>
#include <string.h>
#include <stdlib.h>

long long flt(long long *data, size_t n, size_t rlen, char most) {
    size_t nused = n;
    char used[n];
    memset(used, 1, n);

    for (size_t b = 0; b < rlen; b++) {
        size_t bitcnt[2][rlen];
        memset(bitcnt[0], 0, rlen * sizeof(size_t));
        memset(bitcnt[1], 0, rlen * sizeof(size_t));

        for (size_t i = 0; i < n; i++) {
            if (used[i]) {
                if ((data[i] >> (rlen - b - 1)) & 1)
                    bitcnt[1][b]++;
                else
                    bitcnt[0][b]++;
            }
        }

        if (nused > 1) {
            char cond;
            if (bitcnt[0][b] == bitcnt[1][b])
                cond = most;
            else
                cond = (bitcnt[0][b] > bitcnt[1][b]) ? !most : most;

            for (size_t i = 0; i < n; i++) {
                if (used[i]) {
                    if (((data[i] >> (rlen - b - 1)) & 1) != cond) {
                        used[i] = 0;
                        nused--;
                    }
                }
            }
        }

        if (nused == 1) {
            for (size_t i = 0; i < n; i++) {
                if (used[i])
                    return data[i];
            }
        }
    }

    return 0;
}

int main(void) {
    FILE *fp = fopen("input.txt", "r");
    char buf[16], *end;
    size_t n = 0;
    long long data[1000] = {0};

    while (fgets(buf, sizeof(buf), fp) != NULL) {
        data[n] = strtoll(buf, &end, 2);
        n++;
    }

    printf("Answer: %lld\n",
           flt(data, n, end - buf, 1) * flt(data, n, end - buf, 0));
}