#include<stdio.h>

int main(void){
	int n,a,b,c,d[16]={0},i,r = 0,m = 0;
	scanf("%d",&n);
	for(i = 1;i <= n;i++){
		scanf("%d%d%d",&a,&b,&c);
		d[a]++;d[b]++;d[c]++;
	}
	for(i = 1;i <= 10;i++){
		r+=(d[i]/2);m+=(d[i]%2);
	}
	r+=(m/4);
	printf("%d\n",r);
	return 0;
}