#include <bits/stdc++.h>

using namespace std;
int main() {
    int n,c=0;
    int k;
    int x;
    cin >> n >> k >> x;
 //   /*long answer =*/ countArray(n, k, x);
   //cout << answer << endl;
    int k1[n];
    for(int i=1;i<=n;i++){
        if(i<k)
            k1[i]=i;
        else if(i>k)
            k1[i]=i-k;
       // cout<<k1;
        if(k1[i]<k1[i+1] && k1[i]==k1[i+1])
            swap(k1[i],k1[i+1]);
            c++;
    }
    cout<<c-1;
    return 0;
}