var a,a1,a2,a3: integer;
begin
readln(a);
a1:=a div 100;
a2:=a div 10 mod 10;
a3:=a mod 10;
writeln(a1+a2+a3);
end.
var a,a1,a2,a3: integer;
begin
readln(a);
a1:=a div 100;
a2:=a div 10 mod 10;
a3:=a mod 10;
writeln(a1+a2+a3);
end.