var
s:string;
m:set of Char;
i,k:integer;
begin
readln(s);
m:=[];
for i:=1 to length(s) do
if not(s[i] in m) then
begin
m:=m+[s[i]];
inc(k);
end;
writeln(k);
end.
var
s:string;
m:set of Char;
i,k:integer;
begin
readln(s);
m:=[];
for i:=1 to length(s) do
if not(s[i] in m) then
begin
m:=m+[s[i]];
inc(k);
end;
writeln(k);
end.