LCA（倍增）

type arr=record v,nt:longint; end;
const maxn=; lx=;
var lt:array[..maxn] of longint;
    eg:array[..maxn*] of arr;
    d:array[..maxn] of longint;
    g:array[..maxn,..lx] of longint;
    n,i,x,y,a,b,sum:longint;
procedure swap(var a,b:longint);
var c:longint;
begin
    c:=a; a:=b; b:=c;
end;
procedure add(x,y:longint);
begin
    inc(sum); eg[sum].nt:=lt[x]; eg[sum].v:=y; lt[x]:=sum;
end;
procedure Tinit(x,fa:longint);
var i:longint;
begin
    g[x,]:=fa; d[x]:=d[fa]+;
    for i:= to lx do
        g[x,i]:=g[g[x,i-],i-];
    i:=lt[x];
    while i<> do
    begin
                if eg[i].v<>fa then Tinit(eg[i].v,x);
        i:=eg[i].nt;
    end;
end;
function Tlca(x,y:longint):longint;
var dep,i:longint;
begin
    if d[x]<d[y] then swap(x,y);
    dep:=d[x]-d[y];
    for i:= to lx- do
        if dep and (<<i) > then
            x:=g[x,i];
    if x=y then exit(x);
    for i:=lx- downto  do
        if g[x,i]<>g[y,i] then
        begin
            x:=g[x,i];
            y:=g[y,i];
        end;
    exit(g[x][]);
end;
function Tdist(x,y:longint):longint;
begin
    exit(d[x]+d[y]-d[Tlca(x,y)]*);
end;
begin
    readln(n,a,b);
    sum:=;
    while not eof do
    begin
        read(x);
        while not eoln do
        begin
            read(y);
            add(x,y);
            add(y,x);
        end;
        readln;
    end;
    Tinit(,);
    writeln(Tlca(a,b));
    writeln(Tdist(a,b));
end.