var i,N:integer;
Var s: string;
Begin
Readln(N);
Readln(s);
i:=1;
While ( i <> length(s)-1) do begin
If (((s[i]='R') and (s[i+1]='U')) or ((s[i]='U') and (s[i+1]='R'))) then begin
n:=n-1;
if length(s)-3>=i then
i:=i+1;
end;
i:=i+1;
end;
Writeln (N);
End.