#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=n-1;i>=0;i--)
#define lper(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
template<class T> inline bool chmin(T& a, T b){
    if(a>b){a = b;return true;}return false;}
template<class T> inline bool chmax(T& a, T b){
    if(a<b){a=b;return true;}return false;}
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9;
const ll INF=4e18;
const ll dy[4]={1,0,-1,0};
const ll dx[4]={0,-1,0,1};
int main(){
    vl info(10);
    int N;cin>>N;
    while (N--){
        int a,b,c;cin>>a>>b>>c;
        info[--a]++;
        info[--b]++;
        info[--c]++;
    }
    int ans=0,count=0;
    rep(i,10){
        ans+=info[i]/2;
        count+=info[i]%2;
    }
    cout<<ans+count/4<<endl;
    return 0;
}