#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double dou;
#define pii pair<int, int>
#define fi first
#define se second
#define pb push_back
#define MASK(x) (1LL<<(x))
#define BIT(x, j) (((x)>>(j))&1)
template<typename T> bool maximize(T &x, const T &y) {
if (x < y) {x = y; return 1;}
return 0;
}
template<typename T> bool minimize(T &x, const T &y) {
if (x > y) {x = y; return 1;}
return 0;
}
namespace modulofunc{
const int mod = 1e9+7;
void ad(int &x, int y) {
ll temp = x+y;
if (temp >= mod) temp -= mod;
x = temp;
}
int add(int x, int y) {
ll temp = x+y;
if (temp >= mod) temp -= mod;
return temp;
}
int sub(int x, int y) {
ll temp = x-y;
if (temp < 0) temp += mod;
return temp;
}
int mul(int x, int y) {
return 1LL*x*y%mod;
}
}
using namespace modulofunc;
const int maxn = 2005;
int n, cs, cf;
int dp[maxn][maxn];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
// #define name "task"
// if (fopen(name".inp", "r")) {
// freopen(name".inp", "r", stdin);
// freopen(name".out", "w", stdout);
// }
cin >> n >> cs >> cf;
memset(dp, 0, sizeof(dp));
dp[0][0] = 1;
for (int i = 0; i < n; i++) {
for (int j = 0; j <= i; j++) {
if (!dp[i][j]) continue;
if (i+1 == cs || i+1 == cf) {
ad(dp[i+1][j], dp[i][j]); //join >
ad(dp[i+1][j+1], dp[i][j]); //new <
}
else {
//join
if (i > 1) ad(dp[i+1][j-1], mul(dp[i][j], j-1));
//new
ad(dp[i+1][j+1], mul(dp[i][j], j-1+(i+1<cs)+(i+1<cf)));
}
}
}
cout << dp[n][1];
}
