program Project1;
const k=5;
var a:array [1..k] of integer;
i,ch,max,min,f:integer;
begin
for i:=1 to k do readln(a[i]);
max:=a[1]; min:=a[1];
for i:=2 to k do
begin
if max<a[i] then max:=a[i];
if min>a[i] then min:=a[i];
end;
for ch:=min+1 to max-1 do
begin
f:=0;
for i:=1 to k do
if a[i]=ch then f:=1;
if f=0 then writeln(ch);
end;
readln;
end.