var
n,k,p,c,m,ans,i,j:longint;
col,sum:array[0..50]of longint;
begin
  readln(n,k,p);
  for i:=1 to n do
    begin
      readln(c,m);
      inc(col[c]);
    if m<=p then
      begin
        inc(ans,col[c]-1);
        for j:=0 to k-1 do
          begin
            inc(ans,sum[j]*col[j]);
            sum[j]:=sum[j]+col[j];
            col[j]:=0;
          end;
      end;
    end;
  for j:=0 to k-1 do
    inc(ans,sum[j]*col[j]);
    writeln(ans);
end.

/**************************************************************
	Problem: 2305
	User: admin
	Language: Pascal
	Result: Wrong Answer
****************************************************************/