#include <iostream>
using namespace std;
int main()
{
int n;
cin>>n;
if(n%2==0)
cout<<n+1;
else
cout<<n+2;
return 0;
}
#include <iostream>
using namespace std;
int main()
{
int n;
cin>>n;
if(n%2==0)
cout<<n+1;
else
cout<<n+2;
return 0;
}