#include <stdio.h>

void main(void){
	int enemy = 0;
	int input = scanf("%d\n",&enemy);
	int numberList[10];
	int level = 0;
	for(int i = 0; i < enemy*3 ; i++){
		int drop = 0;
		input = scanf("%d",&drop);
		numberList[drop-1]++;
		if(numberList[drop-1] == 2){
			numberList[drop-1] = 0;
			level++;
		}
	}
	int count = 0;
	for(int i = 0 ; i < 10;i++){
		if(numberList[i] != 0){
			count++;
		}
		if(count == 4){
			count = 0;
			level++;
		}
	}
	printf("%d\n",level);
}