#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll MOD=1e9+7;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
ll N, S, F;
cin>>N>>S>>F;
if(F<S) swap(S, F);
ll diff=N-F;
vector<vector<ll>> A(N+1, vector<ll>(N+1));
vector<vector<ll>> D(N+1, vector<ll>(N+1));
vector<vector<ll>> H(N+1, vector<ll>(N+1));
H[2][2]=1;
ll lastsum=1;
for(int n=3; n<=N; n++) {
ll cursum=0;
for(int j=2; j<=n; j++) {
if(j==2) {
if(n%2) H[n][j]=lastsum;
}
else {
if(n%2) H[n][j]=(H[n][j-1]-H[n-1][j-1]+MOD)%MOD;
else H[n][j]=(H[n][j-1]+H[n-1][j-1])%MOD;
}
cursum=(cursum+H[n][j])%MOD;
}
lastsum=cursum;
}
for(int i=1; i<=S; i++) {
for(int j=i+1; j<=F; j++) {
if(i==1) {
A[i][j]=H[j+diff][j];
} else {
A[i][j]=(A[i-1][j]-D[i-1][j-1]+MOD)%MOD;
D[i][j]=(D[i-1][j]+A[i-1][j-1])%MOD;
}
}
}
cout<<(A[S][F]+D[S][F])%MOD<<'\n';
return 0;
}
