#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ar array
#define vt vector
#define pq priority_queue
#define pu push
#define pub push_back
#define em emplace
#define emb emplace_back
#define mt make_tuple
#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define allp(x, l, r) x.begin() + l, x.begin() + r
#define len(x) (int)x.size()
#define uniq(x) unique(all(x)), x.end()
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template<class Fun> class y_combinator_result {
Fun fun_;
public:
template<class T> explicit y_combinator_result(T &&fun): fun_(std::forward<T>(fun)) {}
template<class ...Args> decltype(auto) operator()(Args &&...args) { return fun_(std::ref(*this), std::forward<Args>(args)...); }
};
template<class Fun> decltype(auto) y_combinator(Fun &&fun) { return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun)); }
template <class T, size_t N>
void re(array <T, N>& x);
template <class T>
void re(vt <T>& x);
template <class T>
void re(T& x) {
cin >> x;
}
template <class T, class... M>
void re(T& x, M&... args) {
re(x), re(args...);
}
template <class T>
void re(vt <T>& x) {
for(auto& it : x) re(it);
}
template <class T, size_t N>
void re(array <T, N>& x) {
for(auto& it : x) re(it);
}
template <class T, size_t N>
void wr(const array <T, N>& x);
template <class T>
void wr(const vt <T>& x);
template <class T>
void wr(const T& x) {
cout << x;
}
template <class T, class ...M>
void wr(const T& x, const M&... args) {
wr(x), wr(args...);
}
template <class T>
void wr(const vt <T>& x) {
for(auto it : x) wr(it, ' ');
}
template <class T, size_t N>
void wr(const array <T, N>& x) {
for(auto it : x) wr(it, ' ');
}
template<class T, class... M>
auto mvt(size_t n, M&&... args) {
if constexpr(sizeof...(args) == 1)
return vector<T>(n, args...);
else
return vector(n, mvt<T>(args...));
}
void set_fixed(int p = 0) {
cout << fixed << setprecision(p);
}
void set_scientific() {
cout << scientific;
}
void Open(const string& name) {
#ifndef ONLINE_JUDGE
(void)!freopen((name + ".in").c_str(), "r", stdin);
(void)!freopen((name + ".out").c_str(), "w", stdout);
#endif
}
const int mod = 1e9 + 7;
template <const int MOD>
struct modint {
ll x;
modint(): x(0) {}
modint(ll x): x((x % MOD + MOD) % MOD) {}
inline modint <MOD>& fix() {
x = (x % MOD + MOD) % MOD;
return *this;
}
inline modint <MOD> operator + (modint<MOD> other) const {
ll c = x + other.x;
return modint<MOD>(c);
}
inline modint <MOD> operator - (modint<MOD> other) const {
ll c = x - other.x;
return modint<MOD>(c);
}
inline modint <MOD> operator * (modint<MOD> other) const {
ll c = (ll)x * other.x;
return modint<MOD>(c);
}
inline modint <MOD>& operator += (modint<MOD> other) {
x += other.x;
this-> fix();
return *this;
}
inline modint <MOD>& operator -= (modint<MOD> other) {
x -= other.x;
this-> fix();
return *this;
}
inline modint <MOD>& operator *= (modint<MOD> other) {
x = (x * other.x) % MOD;
this-> fix();
return *this;
}
inline modint <MOD> operator - () const {
return modint<MOD>(-x);
}
// (++x)
inline modint<MOD>& operator++() {
x = (x + 1);
this-> fix();
return *this;
}
// (x++)
inline modint<MOD> operator++(int) {
modint<MOD> tmp(*this);
++(*this);
return tmp;
}
// (--x)
inline modint<MOD>& operator--() {
x = (x - 1);
this-> fix();
return *this;
}
// (x--)
inline modint<MOD> operator--(int) {
modint<MOD> tmp(*this);
--(*this);
return tmp;
}
explicit operator long long() const {
return x;
}
ll inv(ll a, ll b) const {
return 1 < a? b - inv(b % a, a) * b / a : 1;
}
modint<MOD> lgput(modint<MOD> a, ll b) const {
modint<MOD> res = 1;
while (b) {
if (b & 1)
res = res * a;
a = a * a;
b >>= 1;
}
return res;
}
inline modint<MOD> operator^(ll b) {
return lgput(*this, b);
}
inline modint<MOD> operator ~() const {
return modint<MOD>(inv(this->x, MOD));
}
inline modint<MOD> operator / (modint<MOD> other) const {
return *this * (~other);
}
inline modint<MOD>& operator /= (modint<MOD> other) {
return *this *= (~other);
}
inline bool operator == (modint<MOD> other) const {
return x == other.x;
}
inline bool operator != (modint<MOD> other) const {
return x != other.x;
}
inline bool operator < (modint<MOD> other) const {
return x < other.x;
}
inline bool operator > (modint<MOD> other) const {
return x > other.x;
}
};
template <const int MOD> modint<MOD> operator + (ll value, modint<MOD> n) {
return modint<MOD>(modint<MOD>(value) + n);
}
template <const int MOD> modint<MOD> operator + (int value, modint<MOD> n) {
return modint<MOD>(modint<MOD>(value) + n);
}
template <const int MOD> modint<MOD> operator - (ll value, modint<MOD> n) {
return modint<MOD>(modint<MOD>(value) - n);
}
template <const int MOD> modint<MOD> operator - (int value, modint<MOD> n) {
return modint<MOD>(modint<MOD>(value) - n);
}
template <const int MOD> modint<MOD> operator * (ll value, modint<MOD> n) {
return modint<MOD>(modint<MOD>(value) * n);
}
template <const int MOD> modint<MOD> operator * (int value, modint<MOD> n) {
return modint<MOD>(modint<MOD>(value) * n);
}
template <const int MOD> istream& operator >> (istream& in, modint<MOD> n) {
return in >> n.x;
}
template <const int MOD> ostream& operator << (ostream& out, modint<MOD> n) {
return out << n.x;
}
using mint = modint<mod>;
void solve() {
int n, a, b; re(n, a, b);
vt <vt <mint>> dp(n + 1, vt <mint>(n + 1));
dp[1][1] = 1;
for (int i = 2; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
if (i == a || i == b)
dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j];
else
dp[i][j] = dp[i - 1][j + 1] * j +
dp[i - 1][j - 1] * (j - (i >= a) - (i >= b));
}
}
wr(dp[n][1], '\n');
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//Open("");
int t = 1;
for(;t;t--) {
solve();
}
return 0;
}
