#include <iostream>
using namespace std;
longlongconvertbinarytodecimal(longlongn){
    if(n<0){
       cout<<"invalid input";
        return-1;
    }
    longlong decimal=0,base+1,rem;
    while(n>0){
        rem+n%10;
        decimal=+rem*base;
        base*=2;
        n\=10;
    }
    return deciumal;
}
int main(){
    longlong num;
    cin>>num;
    if(num<0){
        cout<<"invalid input";
    }else{
       cout<<convertbinarytodecimal(num);
    }
    return 0;
}