#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
template<class... T> void dbg(T... x) { char e{}; ((cerr << e << x, e = ' '), ...); }
#define debug(x...) dbg(#x, '=', x, '\n')
#else
#define debug(...) ((void)0)
#endif
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define ff first
#define ss second
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using i128 = __int128;
using u128 = unsigned __int128;
template<class T> inline constexpr T inf = numeric_limits<T>::max() / 2;
constexpr int mod = 1e9 + 7, inv2 = (mod + 1) / 2;
template<class T> bool chmin(T &a, T b) { return (b < a and (a = b, true)); }
template<class T> bool chmax(T &a, T b) { return (a < b and (a = b, true)); }
void solve() {
int n, s, t;
cin >> n >> s >> t;
int op = s > 1;
int ed = t > 1;
vector dp(n + 1, array<i64, 3>{});
dp[1][0] = 1;
for (int i = 2; i <= n; i++) {
decltype(dp) f(n + 1, array<i64, 3>{});
for (int j = 1; j < i; j++) {
if (i == s or i == t) {
f[j][1] += dp[j][0];
f[j][2] += dp[j][1];
f[j + 1][0] += dp[j][0];
f[j + 1][1] += dp[j][1];
f[j + 1][2] += dp[j][2];
} else {
for (int x : {0, 1, 2}) {
f[j - 1][x] += dp[j][x] * (j - 1);
f[j + 1][x] += dp[j][x] * (i - 1 - j + op + ed - x);
}
}
}
if (s == i) op = 0;
if (t == i) ed = 0;
dp.swap(f);
for (auto &x : dp)
for (auto &v : x) v %= mod;
}
cout << (dp[1][0] + dp[1][1] + dp[1][2]) % mod << '\n';
}
signed main() {
cin.tie(0)->sync_with_stdio(false);
cin.exceptions(cin.failbit);
int T = 1;
// cin >> T;
while (T--) {
solve();
}
return 0;
}
