Codeforces 268A

#include <stdio.h>
 
#define Maxsize 50
 
struct uniform
{
	int h;
	int g;
};
 
int main()
{
	int n;
	scanf("%d", &n);
	struct uniform Set[Maxsize];
	int i;
	for(i=0; i<n; ++i)
	{
		scanf("%d%d", &Set[i].h, &Set[i].g);
	}
	int j;
	int Count=0;
	for(i=0; i<n; ++i)
	{
		for(j=0; j<n; ++j)
		{
			if(i!=j)
			{
				if(Set[i].h==Set[j].g)
					++Count;
			}
		}
	}
	printf("%d\n", Count);
	return 0;
}