1
n = int(input())
2
h = [0 for i in range(n)]
3
a = [0 for i in range(n)]
4
 
5
for i in range(n):
6
    h[i], a[i] = map(int, input().split())
7
 
8
ans = 0
9
 
10
for i in range(n):
11
    for j in range(n):
12
        if i != j and h[i] == a[j]:
13
            ans += 1
14
            
15
print(ans)