#include <iostream>

using namespace std;

int main()
{
    string in;
    
    int counts[12] = {0};
	
	int result = 0;
    
    while(cin >> in) for(int i = 0; i < 12; i++) counts[i] = (in[i]=='1')?(counts[i]+1):(counts[i]-1);
    
    for(int i = 0; i < 12; i++) result |= ((counts[i]>0)?1:0)<<(11-i);
    
    cout << result*(result^0x0FFF) << endl;

    return 0;
}