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