import java.io.*;
import java.util.*;
public class kangaroo {
static int[][] X;
static int v;
static int[][][] dp;
public static void main(String[] args)throws IOException {
// TODO Auto-generated method stub
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));
StringTokenizer st = new StringTokenizer(br.readLine());
int n = Integer.parseInt(st.nextToken());
int s = Integer.parseInt(st.nextToken());
int e = Integer.parseInt(st.nextToken());
long[][] dp = new long[n+1][n+1];
if(s>e) {
int save = s;
s = e;
e = save;
}
long mod = 1000000007;
dp[1][1] = 1;
for(int i=2; i<=n; i++) {
for(int j=1; j<=i; j++) {
if(dp[i-1][j]==0)continue;
if(i==s||i==e) {
dp[i][j+1] = (dp[i][j+1]+dp[i-1][j])%mod;
dp[i][j] = (dp[i][j]+dp[i-1][j])%mod;
continue;
}
if(i<s) {
dp[i][j+1] = (dp[i][j+1]+dp[i-1][j]*(j+1))%mod;
dp[i][j-1] = (dp[i][j-1]+dp[i-1][j]*(j-1))%mod;
}
else if(i>s&&i<e) {
dp[i][j+1] = (dp[i][j+1]+dp[i-1][j]*(j))%mod;
dp[i][j-1] = (dp[i][j-1]+dp[i-1][j]*(j-1))%mod;
}
else {
dp[i][j+1] = (dp[i][j+1]+dp[i-1][j]*(j-1))%mod;
dp[i][j-1] = (dp[i][j-1]+dp[i-1][j]*(j-1))%mod;
}
}
}
System.out.println(dp[n][1]);
}
}
