1.#include <iostream>
using namespace std;
int n,m;
int main()
{
cin>>n;
while (n)
{
if (n%2==0)
m=m*10+n%10;
n/=10;
}
cout<<m;
}
2.#include <iostream>
using namespace std;
int n,m;
int main()
{
cin>>n;
cout<<(n/100)%10;
}
3.#include <iostream>
using namespace std;
int i,n;
int main()
{
cin>>n;
for (i=1;i<=4;i++)
{
n=(n%10)*10000+n;
n/=10;
cout<<n<<" ";
}
}