#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <ll,ll> pll;
typedef pair <int,int> pii;
typedef pair <int,pii> piii;
#define forr(_a,_b,_c) for(int _a = (_b); _a <= (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < (_c); ++_a)
#define st first
#define nd second
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"
template<class X, class Y>
bool minz(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} return false;
}
template<class X, class Y>
bool maxz(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} return false;
}
const int N = 5e5 + 5;
const ll oo = (ll) 1e16;
const ll mod = 1e9 + 7; // 998244353;
ll n, s, e, dp[2007][2007];
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef hqm
freopen(file".inp", "r", stdin); freopen(file".out", "w", stdout);
#endif
cin >> n >> s >> e;
s--;
e--;
dp[0][0] = 1;
forf (i, 0, n){
forr (j, 0, i){
if (i == s || i == e){
(dp[i + 1][j+1] += dp[i][j]) %= mod;
(dp[i + 1][j] += dp[i][j]) %= mod;
} else {
(dp[i + 1][j+1] += dp[i][j] * (j - 1 + (i < s) + (i < e))) %= mod;
if (j > 1)
(dp[i + 1][j - 1] += dp[i][j] * (j - 1)) %= mod;
}
}
}
cout << dp[n][1] << "\n";
return 0;
}
/*
*/
