#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define pli pair<ll, int>
#define pil pair<int, ll>
#define pll pair<ll, ll>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
#define endl '\n'
const int inf = 1000000007;
const ll INF = 1e18;
// int mod = 998244353;
int mod = 1000000007;
#define abs(x) (x >= 0 ? x : -(x))
#define lb(v, x) (int)(lower_bound(all(v), x) - v.begin())
#define ub(v, x) (int)(upper_bound(all(v), x) - v.begin())
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return 1; } return 0; }
ll gcd(ll a, ll b) { if (b == 0) return a; return gcd(b, a % b); }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
template<typename T, typename U> T pow_(T a, U b) { return b ? pow_(a * a, b / 2) * (b % 2 ? a : 1) : 1; }
ll modpow(ll a, ll b, ll _mod) { return b ? modpow(a * a % _mod, b / 2, _mod) * (b % 2 ? a : 1) % _mod : 1; }
template<class T, class U> ostream& operator << (ostream& os, const pair<T, U>& p) { os << p.F << " " << p.S; return os; }
template<class T> ostream& operator << (ostream& os, const vector<T>& vec) { rep(i, sz(vec)) { if (i) os << " "; os << vec[i]; } return os; }
template<class T> ostream& operator << (ostream& os, const set<T>& s) { for (auto e : s) os << e << " "; return os; }
template<typename T> inline istream& operator >> (istream& is, vector<T>& v) { rep(j, sz(v)) is >> v[j]; return is; }
template<class T, class T2> inline void add(T &a, T2 b) { (a += b % mod) %= mod; if (a < 0) a += mod; }
template<class T> void operator += (vector<T>& v, vector<T> v2) { rep(i, sz(v2)) v.eb(v2[i]); }


void solve();

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(12); // debuged
  int T;
  T = 1;
  while (T--) solve();
}

// https://atcoder.jp/contests/abc172/submissions/14781083
struct mint {
  ll x;
  mint (ll x = 0) : x(x >= 0 ? x % mod : (mod + x % mod) % mod) {}
  mint operator -() const { return mint(-x); } // 前に数がない
  mint& operator += (const mint a) { // コンストラクタの、modで割った余りがくる
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator -= (const mint a) {
    if ((x += -a.x + mod) >= mod) x -= mod;
    return *this;
  }
  mint& operator *= (const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator + (const mint a) const {
    mint res(*this);
    return res += a; // ?
  }
  mint operator - (const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator * (const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(ll t) const { // mint(a).pow(t) tは余りとったりしたらあかん
    if (t == 0) return 1;
    mint a = pow(t >> 1); // 再帰
    a *= a;
    if (t & 1) a *= *this;
    return a;
  }
  // 逆元
  mint inv() const {
    return pow(mod - 2);
  }
  mint& operator /= (const mint a) { // invを利用
    return (*this) *= a.inv();
  }
  mint operator / (const mint a) const {
    mint res(*this);
    return res /= a;
  }
  friend ostream &operator<<(ostream &s, mint a) { return s << a.x; }
};

struct COM {
  vector<mint> fac, finv;
  COM(int n) : fac(n + 1), finv(n + 1) {
    assert(n < mod);
    fac[0] = 1;
    rep3(i, 1, n + 1) fac[i] = fac[i - 1] * i;
    finv[n] = fac[n].inv();
    for (int i = n; i >= 1; --i) finv[i - 1] = finv[i] * i;
  };
  mint operator() (int n, int k) {
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * finv[k] * finv[n - k];
  }
  mint p(int n, int k) { return fac[n] * finv[n - k]; }
} c(1000005); // 実引数なしでできない

void solve() {
  int x, y;
  cin >> x >> y;

  mint ans = 0;
  rep(i, x + 1) { // (i+1,j+2)
    int cnt = x - i;
    if (cnt % 2) continue;
    cnt /= 2;
    if (i * 2 + cnt != y) continue;
    ans += c(i + cnt, i);
  }
  cout << ans << endl;
}


Measured memory_bytes: 18652