include Math
def pi1(n)
  m=0
  for i in 1..n
    x=rand
    y=rand
    if(x*x+y*y)<1.0
      m+=1
    end
  end
  4.0*m/n
end
def pi2(n)
  r=0.0
  for i in 1..n
    x=rand
    r+=Math.sqrt(1-x*x)
  end
  4.0*r/n
end