var
a: array [1..100, 1..100] of boolean;
depth: array [1..100] of longint;
father: array [1..100, 0..16] of longint;
n, m, i, x, y: longint;
root: longint;

procedure dfs(x: longint);
var
i: longint;
j: longint;
begin
depth[x] := depth[father[x][0]]+1;
j := 1;
while 1<<j<=depth[x]-1 do
begin
father[x][j] := father[father[x][j-1]][j-1];
inc(j);
end;
for i := 1 to n do
begin
if not a[x][i] or (father[x][0] = i) then continue;
father[i][0] := x;
dfs(i);
end;
end;

procedure swap(var x, y: longint);
var
t: longint;
begin
t := x;
x := y;
y := t;
end;

function lca(x, y: longint): longint;
var
t, j: longint;
begin
if depth[x] < depth[y] then
swap(x, y);

t := depth[x] - depth[y];
for j := 0 to 15 do
if t and (1<<j) <> 0 then
x := father[x][j];
if x = y then
exit(x);
for j := 15 downto 0 do
if father[x][j] <> father[y][j] then
begin
x := father[x][j];
y := father[y][j];
end;
lca := father[x][0];
end;

begin
assign(input, 'main.in'); reset(input);
assign(output, 'main.out'); rewrite(output);

read(n, m);
for i := 1 to m do
begin
read(x, y);
a[x, y] := true;
a[y, x] := true;
end;
read(root);
father[root][0] := root;
dfs(root);
while not eof do
begin
read(x, y);
writeln(lca(x, y));
end;

close(input); close(output);
end.