#include <cstdio>

#define FOR(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define REV(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define INC0(i, n) FOR(i, 0, n)
#define INC1(i, n) FOR(i, 1, (n) + 1)
#define DEC0(i, n) REV(i, 0, n)
#define DEC1(i, n) REV(i, 1, (n) + 1)

typedef long long   signed int LL;
typedef long long unsigned int LU;


int n, cnt[10];

int main() {
	scanf("%d", &n);
	INC0(i, n) {
		int a, b, c;
		scanf("%d%d%d", &a, &b, &c); a--; b--; c--;
		cnt[a]++;
		cnt[b]++;
		cnt[c]++;
	}
	
	int ans = 0, m = 0;
	INC0(i, 10) {
		ans += cnt[i] / 2;
		m += cnt[i] % 2;
	}
	
	ans += m / 4;
	
	printf("%d\n", ans);
	
	return 0;
}