#include <bits/stdc++.h>
#ifdef GUDEB
#define D(x) cerr << #x << ": " << (x) << '\n';
#define ifdeb if(true)
#else
#define D(x) ;
#define ifdeb if(false)
#endif
#define all(x) begin(x), end(x)
using namespace std;
using ull = unsigned long long;
using ll = long long;
// #define int ll;
constexpr ll mod = 1000000007;
ll dp[2002][2002];
void solve() {
int n, s, f;
cin >> n >> s >> f;
--s; --f;
dp[0][0] = 1;
for(int i = 0; i < n; ++i) {
if(i == s || i == f) {
// endpoint merge
for(int j = 1; j <= n; ++j) {
dp[i+1][j] += dp[i][j];
dp[i+1][j] %= mod;
}
// endpoint add
for(int j = 0; j < n; ++j) {
dp[i+1][j+1] += dp[i][j];
dp[i+1][j+1] %= mod;
}
} else {
// merge comps
for(int j = 2; j <= n; ++j) {
dp[i+1][j-1] += 1ll*(j-1)*dp[i][j] % mod;
dp[i+1][j-1] %= mod;
}
//add comp
for(int j = 0; j < n; ++j) {
dp[i+1][j+1] += 1ll*(j+1 - (i > s) - (i > f))*dp[i][j] % mod;
dp[i+1][j+1] %= mod;
}
}
}
cout << dp[n][1] << '\n';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout << setprecision(20);
solve();
}
