#include <cstdio>
#include <cmath>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <queue>
#include <vector>
#include <map>
#include <unordered_map>
#include <set>
#include <bitset>
#include <stack>
#include <tuple>
#include <bitset>
#define ll long long
#define ull unsigned long long
#define ld long double
#define fp(a,b,c) for(ll a=b;a<=c;a++)
#define fd(a,b,c) for(ll a=b;a>=c;a--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define inf 0x3f3f3f3f
#define base 127
#define mod 1000000007
#define eb emplace_back
#define pb pop_back
#define y1 y114
#define y0 y514
#define x1 x114
#define x0 x514
#define fill(x,y) memset(x,y,sizeof(x))
#define mpr make_pair
#define met(x,t) memset(x,t,sizeof(x))

using namespace std;

inline int rd(){
	int x = 0, f = 1;char ch = getchar();
	while(ch < '0' || ch > '9'){if(ch == '-')f = -1;ch = getchar();}
	while(ch >= '0' && ch <= '9')x = (x<<1) + (x<<3) + (ch^48),ch = getchar();
	return x * f;}
const int maxN=3000;
int n,s,t;
int f[maxN][maxN];

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	n=rd(),s=rd(),t=rd();
	f[1][1]=1;
	fp(i,2,n){
		fp(j,1,i){
			if(i!=s&&t!=i) f[i][j]=(f[i-1][j+1]*j%mod+(j-(i>s)-(i>t))*f[i-1][j-1]%mod)%mod;
			else f[i][j]=f[i-1][j]+f[i-1][j-1];
		}
	}
	cout << f[n][1] << endl;
	
	return 0;
}