const n=4;
const m=2;
const x=2;
var a:array[1..n] of integer;
b:array[1..m,1..x] of integer;
i,j,d,f:integer;
begin
d:=1;
f:=1;
for i:=1 to n do
readln(a[i]);
for i:=1 to n do
begin
if i mod 2=0 then
begin
b[1,d]:=a[i];
d:=d+1;
end;
if i mod 2<>0 then
begin
b[2,f]:=a[i];
f:=f+1;
end;
end;
for i:=1 to m do
begin
writeln;
for j:=1 to x do
write(b[i,j]);
end;
end.