const
size=100;
var
n,m,x,y,i :integer;
r: array[1.. size] of integer;
map : array[1..size, 1..size] of boolean;
found : boolean;

function successful : boolean;
var
i : integer;
begin
for i :=1 to n do
if not map[r[i]][r[i mod n + 1]]
then begin
successful := false;
exit;
end;
successful :=true;
end;

procedure swap(var a, b : integer);
var
t : integer;
begin
t := a;
a := b;
b := t;
end;

procedure perm(left, right : integer);
var
i : integer;
begin
if found
then exit;
if left > right
then begin
if successful
then begin
for i := 1 to n do
writeln(r[i], ' ');
found := true;
end;
exit;
end;
for i:= left to right do
begin
swap(r[left], r[i]);
perm(left + 1, right);
swap(r[left], r[i]);
end;
end;

begin
readln(n, m);
fillchar(map, sizeof(map), false);
for i := 1 to m do
begin
readln(x, y);
map[x][y] := true;
map[y][x] := true;
end;
for i := 1 to n do
r[i] := i;
found := false;
perm(1, n);
if not found
then writeln('No soloution');
end.

输入:
9 12
1 2
2 3
3 4
4 5
5 6
6 1
1 7
2 7
3 8
4 8
5 9
6 9

输出：1 6 9 5 4 8 3 2 7