#include <bits/stdc++.h>
using namespace std;

int main() {
    long long n,a,b;
    cin >>n >> a>> b;
    if((b-a)%2==0){
        cout << (b-a)/2 << endl;
    }
    else{
        cout << min(a-1,n-b)+((b-a-1)/2)+1 << endl;
    }
}