#include <stdio.h>
#include <string.h>

#define INPUT(str) do{char *p;fgets(str,sizeof(str),stdin);p=strchr(str,'\n');if(p)*p='\0';}while(0)
static char *getinput( char* str );
static char *getinput(char* str) {char c;char *cp;cp=&str[0];c=fgetc(stdin);while( c != EOF ){if((c==' ')||( c=='\n')) break;*cp++=c;c=fgetc(stdin);}*cp='\0';return &str[0];}
#define REP(a,b) for(int a=0;a<(int)(b);++a)
#define INPBUF (4+3)
int	item[100];
// ***********************
int main(void) {
	char str[INPBUF];
	int	query;
	int	val;
	int	ans;
	int	nokori;

	// init
	REP(i,100) item[i] = 0;
	// ready
	INPUT(str); sscanf( str , "%d", &query );
	REP(i,query*3) {
		getinput(str);
		sscanf( str , "%d", &val );
		item[val-1]++;
	}
	// start
	ans = 0;
	nokori = 0;
	REP(i,100) {
		ans += item[i]/2;
		nokori += ( item[i] & 1 );
	}
	ans += nokori / 4;
	printf("%d\n", ans );

	return 0;
}