#include    <stdio.h>

int main(void)
{
    int N;
    int a, b, c;
    int count, i, r;
    int item[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

    scanf("%d", &N);
    for (i = 0; i < N; i++) {
        scanf("%d%d%d", &a, &b, &c);
        item[a - 1]++;
        item[b - 1]++;
        item[c - 1]++;
    }

    count = 0;
    r = 0;
    for (i = 0; i < 10; i++) {
        count += (item[i] / 2);
        r += (item[i] % 2);
    }
    count += (r / 4);

    printf("%d\n", count);

    return 0;
}