n = int(input())
counts = [0] * 10  # 1-based to 10, indexed 0-9

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

# Calculate maximum pairs
pairs = sum(c // 2 for c in counts)

# Sum remaining items after pairs
remaining = sum(c % 2 for c in counts)

# Calculate quadruples from remaining
quadruples = remaining // 4

total = pairs + quadruples
print(total)