#include<stdio.h>
#include<map>
#include<string>
#include<iostream>
using namespace std;
map<pair<string, string>, int>M;
int main() {
	int n, i, j;
	long long ans = 0;
	scanf("%d", &n);
	for (i = 0; i < n; i++) {
		string a, b;
		cin >> a >> b;
		a = a.substr(0, 2);
		if (a == b)continue;
		if (M.find({ b,a })!=M.end())ans += M[{b, a}];
		if (M.find({ a,b })!=M.end())M[{a, b}] = M[{a, b}] + 1;
		else M[{a, b}] = 1;
	}
	printf("%lld", ans);
	return 0;
}

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6
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DALLAS TX
FLINT MI
CLEMSON SC
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ORLANDO FL