program broj;
var s,b:string; a,d,c:integer;
begin
readln(s);
b:=s[3]+s[2]+s[1];
val(b,a,c);
b:=s[7]+s[6]+s[5];
val(b,d,c);
if a>=d then writeln(a) else if d>a then writeln(d);
readln
end.