// explanation of solution at below link
// https://codeforces.com/blog/entry/47764#comment-704139
#include <iostream>
#include <iomanip>
#include <fstream>
#include <vector>
#include <array>
#include <algorithm>
#include <utility>
#include <map>
#include <queue>
#include <set>
#include <cmath>
#include <cstdio>
#include <cstring>
#define ll long long
#define ld long double
#define eps 1e-8
#define MOD 1000000007
#define INF 0x3f3f3f3f
#define INFLL 0x3f3f3f3f3f3f3f3f
// change if necessary
#define MAXN 2010
using namespace std;
int n, cs, cf;
ll dp[MAXN][MAXN];
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> cs >> cf;
dp[1][1] = 1;
for (int i = 2; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (i == cs || i == cf) {
dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1];
if (dp[i][j] >= MOD) dp[i][j] -= MOD;
} else {
dp[i][j] += (dp[i - 1][j + 1]) * j % MOD;
dp[i][j] += (dp[i - 1][j - 1]) * (j - (i > cs) - (i > cf)) % MOD;
if (dp[i][j] >= MOD) dp[i][j] -= MOD;
}
}
}
cout << dp[n][1] << '\n';
return 0;
}
