#include <bits/stdc++.h>


using namespace std;
int a[2005][2005];
int main(){
	int n,x,y;
	cin>>n>>x>>y;
	int s = n / 2;
	if(n % 2){
		s++;
	}
	int d = 1;
	for(int j = 1;j <= s;j++){
		for(int i = j;i <= n - j;i++){
			a[j][i] = d++;
		}
		for(int i = j;i <= n - j;i++){
			a[i][n - j + 1] = d++;
		}
		for(int i = n - j + 1;i >= 1 + j;i--){
			a[n - j + 1][i] = d++;
		}
		for(int i = n - j + 1;i >= 1 + j;i--){
			a[i][j] = d++;
		}
	}
	a[s][s] = d;
	cout<<a[x][y];
	return 0;
}