n = int(input())
counts = [0] * 11  # Using 1-based index for items 1-10

for _ in range(n):
    a, b, c = map(int, input().split())
    counts[a] += 1
    counts[b] += 1
    counts[c] += 1

total_power = 0

# Calculate power-ups from pairs
for i in range(1, 11):
    total_power += counts[i] // 2
    counts[i] %= 2

# Calculate power-ups from remaining items (groups of four)
remaining = sum(counts)
total_power += remaining // 4

print(total_power)