def find_nearest_n(number):
    left = 0
    right = number
    while right-left >= 0.01:
        if ((left+right)/2)**2 == number:
            return (left+right)/2
        elif ((left+right)/2)**2 > number:
            right = (left+right)/2
        else:
            left = (left+right)/2
    if int(right) > int(left):
        return int(right)
    elif left - int(left) < 0.5:
        return int(left)
    else:
        return int(left)+1

应该有还有更好的方法