#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
#define ll long long
#define int ll
#define ld long double
#define pii pair<int,int>
#define all(x) (x).begin(), (x).end()
#define isz(x) (int)(x.size())
#define vi vector<int>
#define vvi vector<vi>
#define ost tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update>
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const int sz = 2200, inf = 1000000000;
const ll mod = 1000000007, INF = 1000000000000000000;
int dp[sz][sz];
void solve(int tc) {
int n, cs, cf;
cin >> n >> cs >> cf;
dp[1][1] = 1;
int cnt = 0;
for (int i = 1; i <= n; i++) {
if (i == cs || i == cf)
cnt++;
for (int j = 1; j < i; j++) {
if (i == cs || i == cf) {
dp[i][j+1] += dp[i-1][j];
dp[i][j] += dp[i-1][j];
dp[i][j+1] %= mod;
dp[i][j] %= mod;
} else {
dp[i][j+1] += (j + 1 - cnt) * dp[i-1][j];
dp[i][j-1] += (j - 1) * dp[i-1][j];
dp[i][j+1] %= mod;
dp[i][j-1] %= mod;
}
}
}
cout << dp[n][1] << '\n';
}
void precompute() {}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
#ifdef LOCAL
freopen("err.log", "w", stderr);
freopen("in.txt", "r", stdin);
#endif
precompute();
int t = 1;
// cin >> t;
for (int tc = 1; tc <= t; tc++) solve(tc);
return 0;
}
