Program Captain;
Var a,b:array[0..50001]of longint; 
F:array[0..26]of longint;S:ansistring;
i,j,Sum:longint;
Begin
Assign(input,'xxxx.in');Reset(input);
Assign(output,'xxxx.out');Rewrite(output);
	Readln(S);
	F[ord(s[1])-96]:=1;a[1]:=1;a[0]:=1;
	For i:=2 to length(s) do begin
		If F[ord(s[i])-96]=0 then begin
			Inc(a[0]);
			a[a[0]]:=i;
			F[ord(s[i])-96]:=a[0];
		End
		else Begin
			B[f[ord(s[i])-96]]:=i;
			F[ord(s[i])-96]:=0;
		End;
	End;Sum:=0;
	For i:=1 to length(s) div 2 do
		For j:=i+1 to length(s) div 2 do begin
			If (a[j]<b[i]) and (b[j]>b[i]) then inc(sum);
			If a[j]>b[i] then break;
		End;
	Writeln(Sum);
Close(input);Close(output);
End.