#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const lint MOD = 1e9 + 7;
int N, S, T;
lint memo[2005][2005][2][2];
lint dp(int n, int comp, int lend, int rend) {
if (comp < 0) {
return 0;
}
if (n == N - 1) {
return comp == 0 ? 1 : 0; // use last piece to merge S and T component
}
lint &res = memo[n][comp][lend][rend];
if (res != -1) {
return res;
}
res = 0;
if (n == S) {
res += dp(n + 1, comp, 1, rend); // make new component
res += dp(n + 1, comp - 1, 1, rend) * comp; // connect a component to left end
} else if (n == T) {
res += dp(n + 1, comp, lend, 1); // make new component
res += dp(n + 1, comp - 1, lend, 1) * comp; // connect a component to right end
} else {
res += dp(n + 1, comp + 1, lend, rend); // add a new component
res += dp(n + 1, comp - 1, lend, rend) * comp * (comp - 1); // merge two components
res += dp(n + 1, comp - 1, lend, rend) * comp * lend; // connect component to left end
res += dp(n + 1, comp - 1, lend, rend) * comp * rend; // connect component to right end
}
res %= MOD;
return res;
}
int main() {
memset(memo, -1, sizeof(memo));
cin >> N >> S >> T;
S--, T--;
cout << dp(0, 0, 0, 0) << "\n";
return 0;
}
