i, j, k, n, p, x, y, min, s, s0: longint;

temp, t: longint;

b: array[0..500] of longint;

a: array[0..400,0..400] of longint;

procedure work(i: longint);

var

ii, j, k, t, s0: longint;

flag: boolean;

root1, root2: integer;

begin

if a[i,0]<=1 then begin

if s<min then min := s;

exit;

end;

s0 := s;

flag := true;

for j := 1 to a[i,0] do if a[a[i,j],0]>0 then begin

flag := false;

s := s0+a[i,0]-1;

if j=1 then root1 := 2 else root1 := 1;

root2 := a[i,root1];

t := a[root2,0];

for k := 1 to t do b[k] := a[root2,k];

for k := 1 to t do if (k<>root1) and (k<>j) then begin

for ii := 1 to a[a[i,k],0] do

a[root2,a[root2,0]+ii] := a[a[i,k],ii];

a[root2,0] := a[root2,0]+a[a[i,k],0];

end;

work(root2);

a[root2,0] := t;

for ii := 1 to t do a[root2,ii] := b[ii];

end;

if flag then begin

s := s0+a[i,0]-1;

if s<min then min := s;

exit;

end;

end;

begin

assign(input,'d:\01.txt');

reset(input);

assign(output,'d:\01out.txt');

rewrite(output);

readln(n,p);

for i := 1 to n do a[i,0] := 0;

for i := 1 to p do begin

readln(x,y);

if x>y then begin

t := x;

x := y;

y := t;

end;

inc(a[x,0]);

a[x,a[x,0]] := y;

end;

s := 1;

min := maxlongint;

work(1);

writeln(min);

close(input);

close(output);

end.

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