use proconio::input;
fn main() {
    let mut a=[0;11];
    input!{
        n:usize,
    }
    let mut ans=0;
    for i in (0..n){
        input!{
            b: [usize;3],
        }
        for j in b{
            if a[j]==1{
                ans+=1;
            }
            a[j]^=1;
        }
    }
    let mut c=0;
    for i in a{
        c+=i;
    }
    ans+=c/4;
    print!("{}",ans);
}