#include <iostream>
using namespace std;
long int x;
int sum=0,contor=0,aux;
int main()
{
cout << "Introduceti un numar mai mic decat 1.000.000.000: \n";
cin>>x;
if(x>1000000000 || x<1){
cout<<"Eroare! Ati introdus un numar prea mare sau unul negativ!"<<endl;
} else{
repeat:
contor++;
aux=x%10;
x=x/10;
if(contor%2==0){
sum+=aux;
}
if(x>0){
goto repeat;
}
cout << sum;
}
return 0;
}
