TONGCS564 PASCAL

var n, b, c, d, a, s:longint;
begin
    assign(input, 'tongcs564.inp');reset(input);
    assign(output, 'tongcs564.out');rewrite(output);
    readln(n);        //n = 2314
    d:=n mod 10;    
    n:=n div 10;    //n = 231
    c:=n mod 10;
    n:=n div 10;    //n = 23
    b:=n mod 10;
    n:=n div 10;    //n = 2
    a:=n;
    s:=a + b + c + d;
    writeln(s);
end.