program ukl;
type
ee=record
 a,b,c,d:char;
 end;
var
f1,f2:text;
r:char;
sum,n,i,j:integer;
s:array[1..1000]of ee;
g:array['a'..'z','a'..'z']of boolean;
begin
assign(f1,'ukl.in');
assign(f2,'ukl.out');
reset(f1);
reset(f2);
readln(f1,n);
for i:= 1to n do readln(s[i].a,s[i].b,s[i].c,s[i].d);
fillchar(g,sizeof(g),0);
sum:=0;
for r := 'a'to 'z'do g[r,r]:=true;
for i:= 1to n do
 if not( g[s[i].b,s[i].d] and g[s[i].c,s[i].d]) then begin
         g[s[i].b,s[i].d]:=true;
         g[s[i].c,s[i].d]:=true;inc(sum);end;
writeln(f2,sum);
close(f1);
close(f2);
end.