import sys from collections import defaultdict n, d, t = int(sys.stdin.readline()), defaultdict(int), 0 for _ in range(n): s, c = sys.stdin.readline().split() d[(s[:2],c)] += 1 for (a,b) in d.keys(): if a<b and (b,a) in d.keys(): t+=d[(a,b)]*d[(b,a)] print(t)