#include <cstdio>
#include <vector>
#define llc (long long)
#define pm %1000000007
using namespace std;
int memo[2001][1001][3];
int n, s, e;
bool valid(int i, int j, int k){
if(i<0||i>n)return false;
if(j<0||j>((n+1)>>1))return false;
if(k<0||k>2)return false;
if(j>i)return false;
// if(i!=n&&k>j)return false;
// if(k>i&&n!=1)return false;// won't happen
return true;
}
int main(){
//obvious goal: find # of perm [0, n) such that tracing 0-1-2 -> zig zag, arr[s]=0, arr[e]=n-1
//inverted goal: find # of perm [0, n) such that value goes up and down, arr[0]=s, arr[n-1]=e
//in inverted goal, k can only increase when value to add is s or e, rest: stick to slide
//honestly, I don't fully understand why the algorithm described in the slide works more practice needed
scanf("%d%d%d", &n, &s, &e);s--;e--;
//pertama kalinya aku pakai %d tanpa spasi
//kelihatannya lebih aman, jadi akan selamanya
//aku pakai ini kecuali ternyata aku salah
memo[0][0][0]=1;
for(int i = 0;i < n;i ++){
for(int j = 0;j <= (n+1)>>1 && j <= i;j ++){
for(int k = 0;k <= 2 && k <= j;k ++){
if(i!=s&&i!=e){//k may not increase
if(valid(i+1, j+1, k)){//new cc
memo[i+1][j+1][k]=(memo[i+1][j+1][k]+llc memo[i][j][k]*(j+1-k)) pm;
}
//apparently, this step is not needed, it just works on paper :P
// if(valid(i+1, j, k)){//stick to cc
// memo[i+1][j][k]=(memo[i+1][j][k]+llc memo[i][j][k]*((j<<1)-k)) pm;
// }
if(valid(i+1, j-1, k)){//merge cc
memo[i+1][j-1][k]=(memo[i+1][j-1][k]+llc memo[i][j][k]*(j-1)) pm;
}
}else{//k may increase
if(valid(i+1, j, k+1)){
memo[i+1][j][k+1]=(memo[i+1][j][k+1]+memo[i][j][k]) pm;
}
if(valid(i+1, j+1, k+1)){
memo[i+1][j+1][k+1]=(memo[i+1][j+1][k+1]+memo[i][j][k]) pm;
}
}
}
}
}
// for(int i = 0;i <= n;i ++){
// for(int j = 0;j <= (n+1)>>1;j ++){
// for(int k = 0;k <= 2;k ++){
// printf("%d ", memo[i][j][k]);
// }
// printf("\n");
// }
// printf("\n");
// }
printf("%d\n", memo[n][1][2]);
}
