#include "bits/stdc++.h" #include <atcoder/all> using namespace std; using namespace atcoder; using ll = long long; using vl = vector<long long>; using pl = pair<long long, long long>; struct edge {long long to;long long cost;edge(long long t,long long c):to(t),cost(c){}}; using Graph = vector<vector<long long>>; using WGraph = vector<vector<edge>>; constexpr int dx[8]{1,0,-1,0,1,1,-1,-1}; constexpr int dy[8]{0,1,0,-1,1,-1,1,-1}; #define rep(i, n) for(long long (i) = 0; (i) < (n); (i)++) #define reps(i, a, b) for(long long (i) = (a); (i) < (b); (i)++) #define rrep(i, a, b) for(long long (i) = (a); (i) >= (b); (i)--) #define all(v) (v).begin(), (v).end() #define pb push_back #define V vector constexpr long long MOD1 = 1000000007; constexpr long long MOD9 = 998244353; constexpr long long INF = numeric_limits<long long>::max() / 8; constexpr long long LL_MAX = std::numeric_limits<long long>::max(); long long safe_mod(long long n, long long m){if(n >= 0) {return n % m;} else return (n%m + m)%m;} long long pw(long long x,long long n) {ll ret=1;while(n>0){if(n&1){ret=ret*x;}if(n>>=1){x=x*x;}}return ret;} template<typename T> T div_ceil(T a,T b){return (a - 1) / b + 1;} template<typename T> T SUM(const vector<T> &v){T ret{};return(accumulate(v.begin(), v.end(), ret));} template<typename T> T MAX(const vector<T> &v){return *max_element(v.begin(), v.end());} template<typename T> T MIN(const vector<T> &v){return *min_element(v.begin(), v.end());} template<typename T> T pwmod(T x, long long n, long long m) {T ret=1;while(n>0){if(n&1)ret=ret*x%m;x=x*x%m;n>>=1;}return ret%m;} template<typename T> void rsort(vector<T> &v) {sort(v.begin(), v.end(), greater<T>());} template<typename T> bool chmax(T &a, const T& b) {if(a<b){a=b;return true;}return false;} template<typename T> bool chmin(T &a, const T& b) {if(a>b){a=b;return true;}return false;} template<typename T, typename S> pair<T, S> mp(const T &a, const S &b){return make_pair(a, b);} template<typename T> void uniquify(vector<T> &v){sort(v.begin(), v.end()); v.erase(unique(v.begin(), v.end()), v.end());} template<typename T,typename S> ostream&operator<<(ostream&os,const pair<T,S>&p){os<<"("<<p.first<<", "<<p.second<<")";return os;} template<typename T,typename S> ostream&operator<<(ostream&os,const map<T,S>&ma){for(auto [a,b]:ma){os<<"("<<a<<", "<<b<<")"<<" ";}return os;} template<typename T> ostream &operator<<(ostream&os,const set<T>&s){os<<"{";for(auto c:s)os<<c<<" ";os<<"}";return os;} template<typename T> ostream &operator<<(ostream&os,const vector<T>&v){os<<"[";for(int i=0;i<v.size();i++){os<<v[i]<<(i==v.size()-1?"":" ");}os<<"]";return os;} template<typename T> vector<int> compress(vector<T> &a){ int n = a.size(); vector<int> ret(n); vector<T> temp = a; sort(a.begin(), a.end()); a.erase(unique(a.begin(), a.end()), a.end()); for(int i = 0; i < n; i++) ret[i] = lower_bound(a.begin(), a.end(), temp[i]) - a.begin(); return ret; } //#define ONLINE_JUDGE #ifdef ONLINE_JUDGE #define dump(x) true #else #define dump(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl #endif using mint = modint1000000007; std::istream &operator>>(std::istream& is, modint1000000007 &m){ int a; is >> a; m = a; return is; } std::ostream &operator<<(std::ostream& os, const modint1000000007 &m){ os << m.val(); return os; } mint operator/(const mint &a, const mint &b){ return a * b.inv(); } const int MAX_N = 4000100; mint fact[MAX_N], fact_inv[MAX_N]; void binom_init(){ fact[0] = 1; fact_inv[0] = 1; for(int i = 1;i < MAX_N; i++){ fact[i] = fact[i-1] * i; fact_inv[i] = fact[i].inv(); } } mint binom(int n, int k){ assert(n >= 0); if(k < 0 || k > n) return 0; return fact[n] * fact_inv[n-k] * fact_inv[k]; } void solve(){ binom_init(); ll a, b, x, y; cin >> a >> b >> x >> y; if((a + x + y) & 1){ cout << 0 << '\n'; return; } mint ans = 0; vl kaisu(4, b / 4); rep(i, (b + 1) % 4) { kaisu[i]++; } rep(xp, a + b + 1) { ll xm = xp - x; ll yp = (a - 2 * xp + x + y) / 2; ll ym = (a - 2 * xp + x - y) / 2; assert(xp + xm + yp + ym == a); if(xp < 0 || yp < 0 || xm < 0 || ym < 0) continue; vl v = {xp, yp, xm, ym}; mint temp = 1; rep(i, 4){ if(v[i] + kaisu[i] - 1 < 0) continue; assert(v[i] + kaisu[i] - 1 < MAX_N); temp *= binom(v[i] + kaisu[i] - 1, v[i]); } ans += temp; } cout << ans << '\n'; } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << std::fixed << std::setprecision(15); solve(); return 0; }