from collections import Counter
n = int(input())
S = []
for _ in range(n):
    a,b,c = map(int,input().split())
    S.append(a)
    S.append(b)
    S.append(c)
ctr = Counter(S)
ret = 0
tank = 0
for k,v in ctr.items():
    if v>=2:
        ret += v//2
    tank += v%2
print(ret + tank//4)