n = int(input())
count = [0]*11
for i in range(n):
    a,b,c = map(int,input().split())
    count[a] += 1
    count[b] += 1
    count[c] += 1
    
ans = 0
m = 0
for i in range(11):
    ans += count[i]//2
    m += count[i]%2
    
print(ans+m//4)