// yukicoder: No.497 入れ子の箱
// 2019.7.14 bal4u

#include <stdio.h>
#include <stdlib.h>

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif

int in() {   // 非負整数の入力
	int n = 0, c = gc();
	do n = 10 * n + (c & 0xf); while ((c = gc()) >= '0');
	return n;
}

#define MAX 1005
#define CMAX 100000000
typedef struct { int x, y, z, id; } T;
T t[MAX+5], s[MAX+5]; int N;
int dp[MAX+5];
int c[2][CMAX+5];

void update(int f, int x, int v) {
	while (x <= CMAX) {
		if (c[f][x] < v) c[f][x] = v;
		x += x & (-x);
	}
}

int getmax(int f, int x) {
	int a = 0;
	while (x > 0) {
		if (a < c[f][x]) a = c[f][x];
		x -= x & (-x);
	}
	return a;
}

void clear(int f, int x) {
	while (x <= CMAX) {
		c[f][x] = 0;
		x += x & (-x);
	}
}

int cmp(const void *a, const void *b) { return ((T *)a)->x - ((T *)b)->x; }
int cmp2(const void *a, const void *b) {
	int t = ((T *)a)->y - ((T *)b)->y; if (t) return t;
	return ((T *)b)->z - ((T *)a)->z;
}

void cdq(int l, int r) {
	int i, k, a, tx, m;

	if (l == r) { if (dp[l] == 0) dp[l] = 1; return; }
	m = (l + r) >> 1;
	tx = t[m + 1].x;
	cdq(l, m);
	k = 0; for (i = l; i <= r; i++) s[k] = t[i], s[k++].id = i;
	qsort(s, k, sizeof(T), cmp2);
	for (i = 0; i < k; i++) {
		if (s[i].id <= m) {
			update(1, s[i].z, dp[s[i].id]);
			if (s[i].x != tx) update(0, s[i].z, dp[s[i].id]);
		} else {
			if (s[i].x == tx) a = getmax(0, s[i].z - 1);
			else a = getmax(1, s[i].z - 1);
			if (dp[s[i].id] < a + 1) dp[s[i].id] = a + 1;
		}
	}
	for (i = 0; i < k; i++) {
		if (s[i].id <= m) {
			clear(1, s[i].z);
			if (s[i].x != tx) clear(0, s[i].z);
		}
	}
	cdq(m + 1, r);
}

int main()
{
	int i, ans;

	N = in(); for (i = 1; i <= N; i++) {
		int tmp, x = in(), y = in(), z = in();
		if (x > y) tmp = x, x = y, y = tmp;
		if (y > z) {
			tmp = y, y = z, z = tmp;
			if (x > y) tmp = x, x = y, y = tmp;
		}
		t[i].x = x, t[i].y = y, t[i].z = z;
	}
	qsort(t+1, N, sizeof(T), cmp);
	
	if (t[1].x == t[N].x) ans = 1;
	else {
		cdq(1, N);
		ans = 0; for (i = 1; i <= N; i++) if (dp[i] > ans) ans = dp[i];
	}
	printf("%d\n", ans);
	return 0;
}