#include <bits/stdc++.h>
using namespace std;
#define MASK(x) (1LL << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
#define ALL(x) (x).begin(), (x).end()
#define REP(i, n) for (int i = 0, _n = n; i < _n; ++i)
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define FORE(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define debug(...) "[" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
template <class A, class B> bool minimize(A &a, B b) { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b) { if (a < b) { a = b; return true; } return false; }
template <int Mod>
struct Modular {
private :
int val;
static int inverse(int a, int b) {
a %= b;
assert(a);
if(a == 1) return 1;
return int(b - (long long) inverse(b, a) * (long long) b / a);
}
public :
Modular(long long x = 0) : val(x % Mod) { if(val < 0) val += Mod; }
friend bool operator == (const Modular &a, const Modular &b) { return a.val == b.val; }
friend bool operator != (const Modular &a, const Modular &b) { return a.val != b.val; }
Modular& operator = (const long long &x) { val = x % Mod; if(val < 0) val += Mod; return *this; }
Modular& operator = (const Modular &x) { val = x.val; return *this; }
friend istream & operator >> (istream &in, Modular &a) { long long x; in >> x; a = Modular(x); return in; }
friend ostream & operator << (ostream &out, const Modular &a) { return out << a.val; }
explicit operator int() const { return val; }
explicit operator bool() const { return val > 0; }
Modular inv() const {
Modular res;
res.val = inverse(val, Mod);
return res;
}
Modular operator ++() { (*this) += 1; return *this; }
Modular operator --() { (*this) -= 1; return *this; }
Modular operator ++(int) { (*this) += 1; return *this - 1; }
Modular operator --(int) { (*this) -= 1; return *this + 1; }
Modular operator + () const { return *this; }
Modular operator - () const {
Modular res;
res.val = (val ? Mod - val : 0);
return res;
}
Modular& operator += (const Modular &a) {
val += a.val;
if(val >= Mod) val -= Mod;
return *this;
}
Modular& operator -= (const Modular &a) {
val -= a.val;
if(val < 0) val += Mod;
return *this;
}
Modular& operator *= (const Modular &a) {
val = 1LL * val * a.val % Mod;
return *this;
}
Modular& operator /= (const Modular &a) {
(*this) *= a.inv();
return *this;
}
friend Modular operator + (const Modular &a, const Modular &b) { return Modular(a) += b; }
friend Modular operator - (const Modular &a, const Modular &b) { return Modular(a) -= b; }
friend Modular operator * (const Modular &a, const Modular &b) { return Modular(a) *= b; }
friend Modular operator / (const Modular &a, const Modular &b) { return Modular(a) /= b; }
};
// const int Mod = 998244353;
// const int Mod = 1e9 + 9; // 1000000009
const int Mod = 1e9 + 7; // 1000000007
using Modint = Modular <Mod>;
template <class T> T pow(T a, long long b) {
T ans = 1, mul = a;
for (; b; b >>= 1) {
if(b & 1LL) ans *= mul;
mul *= mul;
}
return ans;
}
Modint dp[2005][2005];
void you_make_it(void) {
int n, cs, cf; cin >> n >> cs >> cf;
dp[0][0] = 1;
FOR(i, 1, n) {
FOR(j, 1, n) {
if(i == cs || i == cf) {
dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
} else {
dp[i][j] = dp[i - 1][j + 1] * j + dp[i - 1][j - 1] * (j - (i > cs) - (i > cf));
}
}
}
cout << dp[n][1];
}
signed main() {
#ifdef LOCAL
freopen("TASK.inp", "r", stdin);
freopen("TASK.out", "w", stdout);
#endif
auto start_time = chrono::steady_clock::now();
cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
you_make_it();
auto end_time = chrono::steady_clock::now();
cerr << "\nExecution time : " << chrono::duration_cast <chrono::milliseconds> (end_time - start_time).count() << "[ms]" << endl;
return (0 ^ 0);
}
// Dream it. Wish it. Do it.
