#include <stdio.h>

struct a
{
 int a1;
} ;

struct b
{
 int b1;
 struct a b2;
} ;

int main()
{
struct b sb;

sb.b1=1;
sb.b2.a1=2;

printf("%d : %d",sb.b1,sb.b2.a1);
return 0;
}