implicit none
integer(8) i,n,m,j,a,b
integer(8),allocatable :: x(:,:)
integer(8),allocatable :: y(:)
read(*,*) n
allocate (x(1:n+1,1:3))
allocate (y(1:10))
x=0
y=0
a=0
b=0
do i=1,n
    read(*,*) (x(i,m),m=1,3)
    do j=1,3
        y(x(i,j))=y(x(i,j))+1
        if (y(x(i,j))==2) then
            a=a+1
            y(x(i,j))=y(x(i,j))-2
        end if
    end do
end do

do i=1,11
    if (y(i) == 1) then
        b=b+1
    end if
end do

b=b/4

write(*,*) a+b
end