#include <iostream>
#include <string>
#include <sstream>


using namespace std;

int main()
{


   string text="";
   int input=0;
   int a=0;
   int i=0;
   cout << "Zadej cislo ve dvojkove soustave:" << endl;
   getline(cin, text);


   for(i; i < static_cast<int>(text.size()); i++)
    {
        char ch = text[i];

        if((ch != '0') && (ch != '1'))
        {
            cout << "Nespravny vstup." << endl;
            return(0);
        }

    }




    int output = 0;
    int weight = (1ull << (text.size() - 1));

    for(a; a < static_cast<int>(text.size()); a++) {
    output += (text[a] - '0') * weight;
    weight = weight >> 1;
    }

    cout << "Desitkove cislo je: " << output << endl;

    return(0);



 }