#include <iostream>
#include <cmath>

using namespace std;

long long convert (long long n)
{
    int zbytek, decimal = 0, krok = 0;
    while (n!=0)
    {
        zbytek=n%10;
        n=n/10;
        decimal=decimal+(zbytek*pow(2,krok));
        ++krok;
    }
    return decimal;
}



int main()
{
    long long n;
    cout << "Zadej bin: ";
    cin >> n;
    if (!cin.fail())
        {
        if (cin.peek() != '0' || cin.peek() !='1')
        {
          cout << convert(n) ;
        }
          else
        {
          cout << "hovno" << endl;
        }
        }
    else cout << "Spatny vstup." << endl;

    return 0;



}