LL ind(LL x, LL y, LL n){

    LL qs = n / , q = min(n - y + , min(n - x + , min(x, y))) - ;

    if (x == qs +  && y == qs + )    return n * n;

    LL ans = 1ll * q * ( * qs +  * (qs - q + )) / ;

    if (n - x == q)    ans += n - q - y + ;

    else if (y -  == q)    ans += n -  * q +  + n - q -  - x;

    else if (x -  == q)    ans += n -  * q +  + n -  * q -  + y - q - ;

    else ans += n -  * q +  + n -  * q -  + n -  * q -  + x - q - ;

    return ans;

}