#include <bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define ll long long int
#define vi vector<int>
#define vii vector< vector<int> >
#define PI 3.1415926535897932384626433832795
#define INF 9223372036854775807LL
ll ways[10];
bool used[10];
int n,s,f;
int solve(int pos, int did, int from) {
if(did == n && pos == f) {
return 1;
}
used[pos] = true;
int ans = 0;
if(from == -1) {
for(int i = 1; i <= n; i++) {
if(i != pos) {
ans+= solve(i,did+1,(i < pos ? 1 : 0));
}
}
} else if(from == 0) {
for(int i = 1; i < pos; i++) {
if(!used[i]) {
ans+= solve(i,did+1,1);
}
}
} else {
for(int i = pos+1; i <= n; i++) {
if(!used[i]) {
ans+= solve(i,did+1,0);
}
}
}
used[pos] = false;
return ans;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> s >> f;
if(s > f) {
swap(s,f);
}
cout << solve(s,1,-1);
return 0;
}
