#include <cstdio>

int counter[11];

int main(){
    int N;
    scanf("%d", &N);

    for(int i=0;i<N;i++){
        int a, b, c;
        scanf("%d %d %d", &a, &b, &c);

        counter[a] += 1;
        counter[b] += 1;
        counter[c] += 1;
    }

    int res = 0, sum = 0;
    for(int i=1;i<=10;i++){
        res += counter[i] / 2;
        sum += counter[i] % 2;
    }

    printf("%d\n", res + sum/4);
}