#include <stdio.h>

int main(void){
	int i;
	int N;
	int powerUpCount = 0;
	int itemNum[12];
	int rest = 0;
	
	scanf("%d", &N);
	
	for(i=0;i<12;i++){itemNum[i] = 0;}
	
	for(i=0;i<N;i++){
		int A,B,C;
		scanf("%d %d %d", &A, &B, &C);
		
		itemNum[A] += 1;
		if(itemNum[A]>=2){ itemNum[A]-=2; powerUpCount +=1;}
		
		itemNum[B] += 1;
		if(itemNum[B]>=2){ itemNum[B]-=2; powerUpCount +=1;}
		
		itemNum[C] += 1;
		if(itemNum[C]>=2){ itemNum[C]-=2; powerUpCount +=1;}
	}
	
	for(i=0;i<12;i++){
		rest += itemNum[i];
	}
	
	powerUpCount += (rest/4);
	
	printf("%d\n", powerUpCount);
	return 0;
}