var
A:array[1..1000] of integer;
i,s,n,b,r,m,j,k,d,q:integer;
begin
s:=0;
r:=0;
q:=0;
read(n);
for i:=1 to n do readln(A[i]);
begin
for i := 1 to n-1 do
        for j := 1 to n-i do
            if A[j] > A[j+1] then begin
                k := A[j];
                A[j] := A[j+1];
                A[j+1] := k
            end;
            end;

for i:=1 to (n-1) do begin
d:=i+q;
if (A[d]=A[d+1]) then s:=s+1 else s:=0;
if s=3 then begin r:=r+1; s:=0; q:=1+q; end;






end;
write(r);
end.