#include <bits/stdc++.h>
#ifdef GUDEB
#define D(x) cerr << #x << ": " << (x) << '\n';
#define ifdeb if(true)
#else
#define D(x) ;
#define ifdeb if(false)
#endif
#define all(x) begin(x), end(x)
using namespace std;
using ull = unsigned long long;
using ll = long long;
// #define int ll;
constexpr ll mod = 1000000007;
int dp1[2002][2002];
int dp2[2002][2002];
void solve() {
int n, s, f;
cin >> n >> s >> f;
--s; --f;
int (*dp)[2002][2002] = &dp1;
int (*ndp)[2002][2002] = &dp2;
(*dp)[s][f] = 1;
(*dp)[n-s-1][n-f-1] = 1;
for(int i = n-1; i >= 1; --i) {
for(int f = 0; f < i; ++f) {
ll d = 0;
for(int s = 0; s < i; ++s) {
d += (*dp)[s][f + (f <= s)];
d %= mod;
(*ndp)[i-1-s][i-1-f] += d;
(*ndp)[i-1-s][i-1-f] %= mod;
}
}
swap(dp, ndp);
for(int f = 0; f < i; ++f) {
for(int s = 0; s < i; ++s) {
(*ndp)[f][s] = 0;
}
}
}
cout << (*dp)[0][0] << '\n';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout << setprecision(20);
solve();
}
