import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}
void readA(T)(size_t n,ref T[]t){t=new T[](n);auto r=rdsp;foreach(ref v;t)pick(r,v);}

void main()
{
  int n; readV(n);
  int[] a; readA(n, a);

  auto x = new real[](n), y = new real[](n);
  foreach (i; 0..n) {
    x[i] = i;
    y[i] = a[i];
  }

  auto ax = x.sum/n, ay = y.sum/n;
  x[] -= ax; y[] -= ay;

  auto sxy = 0.0L, sx = 0.0L;
  foreach (i; 0..n) {
    sxy += x[i]*y[i];
    sx += x[i]^^2;
  }

  auto d = sxy/sx, b = ay-ax*d;

  auto c = 0.0L;
  foreach (i; 0..n) c += (d*i+b-a[i])^^2;

  writefln("%.7f %.7f", b, d);
  writefln("%.7f", c);
}