#include <bits/stdc++.h>

using namespace std;
long fact(int n){
    long sum=1;
   for(unsigned i=2;i<=n;i++){
       sum*=i;
   } 
    return sum;
}
long countArray(int n, int k, int x) {
    // Return the number of ways to fill in the array.
    if(k>x){
        return fact(k)/fact(n-2);
    }
    else return (fact(k)/fact(n-2))+n;
}

int main() {
    int n;
    int k;
    int x;
    cin >> n >> k >> x;
    long answer = countArray(n, k, x);
    cout << answer << endl;
    return 0;
}