Problem:
Score : 200 points

Problem Statement

There are N bags of biscuits. The i-th bag contains A_i biscuits.

Takaki will select some of these bags and eat all of the biscuits inside.
Here, it is also possible to select all or none of the bags.

He would like to select bags so that the total number of biscuits inside is congruent to P modulo 2.
How many such ways to select bags there are?

Constraints

1 \leq N \leq 50

P = 0 or 1

1 \leq A_i \leq 100

Input

Input is given from Standard Input in the following format:

N P
A_1 A_2 ... A_N

Output

Print the number of ways to select bags so that the total number of biscuits inside is congruent to P modulo 2.

Sample Input 1

2 0
1 3

Sample Output 1

2

There are two ways to select bags so that the total number of biscuits inside is congruent to 0 modulo 2:

Select neither bag. The total number of biscuits is 0.

Select both bags. The total number of biscuits is 4.

Sample Input 2

1 1
50

Sample Output 2

0

Sample Input 3

3 0
1 1 1

Sample Output 3

4

Two bags are distinguished even if they contain the same number of biscuits.

Sample Input 4

45 1
17 55 85 55 74 20 90 67 40 70 39 89 91 50 16 24 14 43 24 66 25 9 89 71 41 16 53 13 61 15 85 72 62 67 42 26 36 66 4 87 59 91 4 25 26

Sample Output 4

17592186044416

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
#define exrep(i, a, b) for(long long i = a; i <= b; i++)
#define rep(i,n)for(long long i=0;i<(long long)(n);i++)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef vector<ll> vl;
typedef vector<vector<ll>> vvl;
typedef pair<ll, ll> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
 
const ll MOD=1e9+7;
const ll INF=1e18;
const int MAX=510000;
const double pi=acos(-1);
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
ll modpow(ll a, ll n){
  if(n==0)return 1;
  if(n%2==0){
    ll t=modpow(a,n/2);
    return t*t%MOD;
  }
  return a*modpow(a,n-1)%MOD;
}
ll modinv(ll a){
  return modpow(a,MOD-2);
}
long long fac[MAX], finv[MAX], inv[MAX];
 
// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}
 
// 二項係数計算
long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
struct UnionFind {
    vector<int> par; // 親ノード
    vector<int> rank; // ランク
 
    UnionFind(int n = 1) {
        init(n);
    }
 
    void init(int n = 1) {
        par.resize(n); rank.resize(n);
        for (int i = 0; i < n; ++i) par[i] = i, rank[i] = 0;
    }
 
    int root(int x) {
        if (par[x] == x) {
            return x;
        }
        else {
            int r = root(par[x]);
            return par[x] = r;
        }
    }
 
    bool issame(int x, int y) {
        return root(x) == root(y);
    }
 
    bool merge(int x, int y) {
        x = root(x); y = root(y);
        if (x == y) return false;
        if (rank[x] < rank[y]) swap(x, y);
        if (rank[x] == rank[y]) ++rank[x];
        par[y] = x;
        return true;
    }
};
vvl G;
ll dfs(int v){
  ll res=1;
  for(auto nv:G[v]){
    res+=dfs(nv);
  }
  return res;
}
    
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false); 
  COMinit();
  
  ll n,p;
  cin >> n >> p;
  int odd=0,even=0;
  rep(i,n){
    ll a;
    cin >> a;
    if(a&1)odd++;
    else even++;
  }
  if(odd==0 && p==1){
    cout << 0 << endl;
  }
  else cout << (ll)pow(2,n-1) << endl;
}