#include <bits/stdc++.h>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
using ll = long long;
using ld = long double;
#define all(s) (s).begin(),(s).end()
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)
#define rever(vec) reverse(vec.begin(), vec.end())
#define sor(vec) sort(vec.begin(), vec.end())
#define fi first
#define se second
#define P pair<ll,ll>
const ll mod = 998244353;
//const ll mod = 1000000007;
const ll inf = 2000000000000000000ll;
static const long double pi = 3.141592653589793;
void vcin(vector<ll> &n){for(int i=0;i<int(n.size());i++) cin>>n[i];}
void vcout(vector<ll> &n){for(int i=0;i<int(n.size());i++){cout<<n[i]<<" ";}cout<<endl;}
void YesNo(bool a){if(a){cout<<"Yes"<<endl;}else{cout<<"No"<<endl;}}
void YESNO(bool a){if(a){cout<<"YES"<<endl;}else{cout<<"NO"<<endl;}}
template<class T,class U> void chmax(T& t,const U& u){if(t<u) t=u;}
template<class T,class U> void chmin(T& t,const U& u){if(t>u) t=u;}
ll modPow(ll a, ll n, ll mod) { ll ret = 1; ll p = a % mod; while (n) { if (n & 1) ret = ret * p % mod; p = p * p % mod; n >>= 1; } return ret; }
using mint = modint998244353;
class UnionFind{
public:
  vector<ll> par;
  vector<ll> siz;
  UnionFind(ll sz_):par(sz_),siz(sz_,1ll){
    for(int i=0;i<sz_;i++) par[i]=i;
  }
  void init(ll sz_){
    par.resize(sz_);
    siz.assign(sz_,1ll);
    for(int i=0;i<sz_;i++) par[i]=i;
  }
  ll root(ll x){
    while(par[x]!=x){
      x=par[x]=par[par[x]];
    }
    return x;
  }
  bool merge(ll x,ll y){
    x=root(x);
    y=root(y);
    if(x==y) return false;
    if(siz[x]<siz[y]) swap(x,y);
    siz[x]+=siz[y];
    par[y]=x;
    return true;
  }
  bool issame(ll x,ll y){
    return root(x)==root(y);
  }
  ll size(ll x){
    return siz[root(x)];
  }
};
int main() {
  /* mod は 1e9+7 */
  ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
  cout<< fixed << setprecision(10);
  ll a,b;
  cin>>a>>b;
  vector<ll> l(a),r(a);
  for(int i=0;i<a;i++){
    cin>>l[i]>>r[i];
    l[i]--;
    r[i]--;
  }
  mint ans=b*a*mint(1-b).pow(a-1);
//  cout<<ans.val()<<endl;
  for(int i=1;i<(1<<a);i++){
    UnionFind t(a);
    vector<ll> g(a);
    bitset<20> s(i);
    for(int j=0;j<a;j++){
      if(s.test(j)){
        g[l[j]]++;
        g[r[j]]++;
        t.merge(l[j],r[j]);
      }
    }
    bool c=true;
    for(int j=0;j<a;j++){
      for(int k=0;k<a;k++){
        if(g[j]&&g[k]){
          if(!t.issame(j,k)){
            c=false;
          }
        }
      }
    }
    if(c){
      ll x=0,y=0;
      for(int j=0;j<a;j++){
        if(g[j]>=2){
          x++;
        }
        if(g[j]==1){
          y++;
        }
      }
      /*cout<<i<<" "<<x<<" "<<y<<" "<<(mint(b).pow(y)*mint(1-b).pow(a-x-y)*(x+y)).val()<<endl;
      for(int j=0;j<a;j++){
        cout<<g[j]<<" ";
      }
      cout<<endl;*/
      ans+=mint(b).pow(y)*mint(1-b).pow(a-x-y)*(x+y);
    }
  }
  cout<<ans.val()<<endl;
}