uses crt;
var n,i:LongInt;
ar:array[1..2000000000] of integer;
f,g:text;
procedure docfile;
begin
assign(f,'nhap.inp');reset(f);
readln(f,n);
for i:=1 to n do read(f,ar[i]);
close(f);
assign(g,'xuat.out');rewrite(g);
end;
function ucln(a:integer;b:integer):integer;
begin
while a<>b do if a>b then a:=a-b else b:=b-a;
ucln:=a;
end;
procedure kt;
var a,b,d:integer;
begin
d:=0;
for i:=1 to n-1 do
begin
a:=ar[i];
b:=ar[i+1];
if ucln(a,b)=1 then
begin
writeln(g,a,' ',b);
inc(d);
end;
end;
if d=0 then write(g,'ko co cap nao');
end;
begin
docfile;
kt;
close(g);
end.