#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define endl '\n'
#define MASK(i) (1LL << (i))
#define ull unsigned long long
#define ld long double
#define pb push_back
#define all(x) (x).begin() , (x).end()
#define BIT(x , i) ((x >> (i)) & 1)
#define TASK "task"
#define sz(s) (int) (s).size()
using namespace std;
const int mxN = 5e5 + 227;
const int inf = 1e9 + 277;
const int mod = 1e9 + 7;
const ll infll = 1e18 + 7;
const int base = 307;
const int LOG = 20;
template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
if (a < b) {a = b; return true;} return false;
}
int n;
int sta;
int fin;
int dp[2007][2007];
void add(int &a, int b)
{
a += b;
if(a >= mod)
a -= mod;
}
void solve()
{
cin >> n >> sta >> fin;
dp[0][0] = 1;
for(int i = 0; i < n; i++) {
for(int j = 0; j <= i; j++) {
if(dp[i][j] == 0) continue;
//cout << i << ' ' << j << ' ' << dp[i][j] << endl;
if(i + 1 == sta) {
add(dp[i + 1][j + 1], dp[i][j]);
if(j > 0) add(dp[i + 1][j], dp[i][j]);
continue;
}
if(i + 1 == fin) {
add(dp[i + 1][j + 1], dp[i][j]);
if(j > 0) add(dp[i + 1][j], dp[i][j]);
continue;
}
add(dp[i + 1][j + 1], 1LL * dp[i][j] * (j + 1 - (i >= sta) - (i >= fin)) % mod);
if(j > 1) add(dp[i + 1][j - 1], 1LL * dp[i][j] * (j - 1) % mod);
}
}
cout << dp[n][1];
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
//freopen(TASK".inp" , "r" , stdin);
//freopen(TASK".out" , "w" , stdout);
int tc = 1;
//cin >> tc;
while(tc--) {
solve();
}
return 0;
}
