#include <stdio.h>
int main()
{
int n;
scanf("%d",&n);
if(n % 2 == 1)
{
n = 3 * n + 1;
}
else
{
n = n / 2;
}
printf("%d",n);
return 0;
}

#include <stdio.h>
int main()
{
int n;
scanf("%d",&n);
if(n % 2 == 1)
{
n = 3 * n + 1;
}
else
{
n = n / 2;
}
printf("%d",n);
return 0;
}