class p069(object):
    def sqrt(self, x):
        if x < 2 :
            return x
        left, right = 1 , x // 2
        while left <= right:
            mid = left + (right - left) // 2
            if mid > x / mid:
                right = mid - 1
            else:
                left = mid + 1
        return left - 1

S = p069()
print S.sqrt(8)