#include <bits/stdc++.h>
using namespace std;
int main(void){
    long long a,b,n;
    cin>>n>>a>>b;
    if((b-a)%2==0){
        cout<<(b-a)/2;
    }
    else{
        cout<<min(a-1,n-b)+1+(b-a-1)/2;
    }
}
