#include <bits/stdc++.h>
#pragma GCC optimize ("Ofast", "unroll-loops")
using namespace std;
#define ll long long
#define int ll
#define FOR(i,a,b) for (int i = (a); i<(b); i++)
#define REP(i,n) FOR(i,0,n)
#define REP1(i,n) FOR(i,1,n+1)
#define RREP(i,n) for (int i=(n)-1; i>=0; i--)
#define f first
#define s second
#define pb push_back
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)(x.size())
#define SQ(x) (x)*(x)
#define pii pair<int, int>
#define pip pair<int, pii>
#define pdd pair<double ,double>
#define pcc pair<char, char>
#define endl '\n'
//#define TOAD
#ifdef TOAD
#define bug(x) cerr<<__LINE__<<": "<<#x<<" is "<<x<<endl
#define IOS()
#else
#define bug(...)
#define IOS() ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#endif
const ll inf = 1ll<<60;
const ll iinf = 2147483647;
const ll mod = 1e9+7;
const ll maxn = 2005;
const ll maxm = 2005;
const double PI=acos(-1);
ll pw(ll x, ll p, ll m=mod){
ll ret=1;
while (p>0){
if (p&1){
ret*=x;
ret%=m;
}
x*=x;
x%=m;
p>>=1;
}
return ret;
}
ll inv(ll a, ll m=mod){
return pw(a,m-2,m);
}
int dp[maxn][maxn];
signed main(){
IOS();
int n, cs, cf; cin>>n>>cs>>cf;
if (cs > cf) swap(cs, cf);
dp[0][0] = 1;
REP1(i, n){
REP1(j, i){
if (i < cs){
dp[i][j] = dp[i-1][j-1] + dp[i-1][j+1]*(j+1)%mod*j%mod;
}
if (i == cs){
dp[i][j] = dp[i-1][j-1] + dp[i-1][j]*j%mod;
}
if (i > cs && i < cf){
dp[i][j] = dp[i-1][j-1] + dp[i-1][j+1]*j%mod*j%mod; // j * (j-1) + 1 * j
}
if (i == cf){
if (i == n && j == 1) dp[i][j] = dp[i-1][j];
else dp[i][j] = dp[i-1][j-1] + dp[i-1][j]*(j-1)%mod;
}
if (i > cf){
if (i == n && j == 1) dp[i][j] = dp[i-1][j+1];
else dp[i][j] = dp[i-1][j-1] + dp[i-1][j+1]*(j-1)%mod*j%mod;
}
dp[i][j] %= mod;
}
}
cout<<dp[n][1]<<endl;
}
