#include <stdio.h>
int main(void){
    int N,a,b,c,x;
    int P=0,p=0;
    int I[10]={};
    scanf("%d",&N);
    for(x=0;x<N;x++){
        scanf("%d %d %d",&a,&b,&c);
        I[a-1]++;
        I[b-1]++;
        I[c-1]++;
    }
    for(x=0;x<10;x++){
        P=P+(I[x]/2);
        p=p+(I[x]%2);
    }
    P=P+(p/4);
    
    printf("%d\n",P);
    
    return 0;
}