//Dedicated to my love, ivaziva
//https://codeforces.com/blog/entry/92602
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
using ll = int64_t;
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define dbg(x) cerr << #x << ": " << x << '\n';
const int N = 2000 + 20;
const int md = 1e9 + 7;
int n, cs, cf;
int dp[N][N];
int ckadd(int a, int b) {
a += b;
if (a >= md) a -= md;
return a;
}
int ckmul(int a, int b) {
a *= b;
if (a >= md) a -= md;
return a;
}
int32_t main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
cerr.tie(nullptr);
cin >> n >> cs >> cf;
dp[1][1] = 1;
for (int e = 2; e <= n; e++) {
for (int pos = 1; pos <= n; pos++) {
if (e == cs || e == cf) {
dp[e][pos] = ckadd(dp[e - 1][pos - 1], dp[e - 1][pos]);
} else {
int diff = (e > cs) + (e > cf);
dp[e][pos] = ckadd(ckmul(dp[e - 1][pos + 1], pos), ckmul(dp[e - 1][pos - 1], pos - diff));
}
}
}
cout << dp[n][1] << '\n';
}
