The positive integer number n is represented by k (40 <=k <= 80) digits in decimal system, and is called large number. The problem is to write a program that, for a given large number n determines the greatest integer such that p3+p2+3p<=n.
Program input will be in an ASCII file named INPUT.2 . The first line contains a large number n with k digits.
Output should be on the standard output (screen) and should contain the integer p only.