uses crt,math;
var a,b,c,d:longint;
procedure ss(var a,b:longint);
var t:longint;
begin
if a>b then
begin
t:=a;a:=b;b:=t;
end;
end;
begin
clrscr;
readln(a,b,c);
ss(a,b);ss(a,c);ss(b,c);
d:=min(c-b,b-a);
if a+d<>b then writeln(a+d)
else if b+d<>c then writeln(b+d)
else writeln(c+d);
readkey;
end.