#include
int ntol( int n )
{
return 6*n-3 ;
}
int lton( int l )
{
return (l+3)/6 ;
}
int main()
{
int n,l;
printf("input n: ");
scanf("%d", &n);
printf("l=%d\n", ntol(n) );
printf("input l: ");
scanf("%d", &l);
printf("n=%d\n", lton(l) );
return 0;
}