Perfect Squares in Descending Order

Given an integer n, your task is to print all the perfect squares from 1 to n (inclusive) in descending order. A perfect square is an integer that is the square of some integer (for example, 1, 4, 9, 16, etc.). If n is less than 1, then there are no perfect squares in the range and you should output nothing.

Examples:

• If n = 16, then the output should be: 16 9 4 1
• If n = 20, then the output should be: 16 9 4 1
• If n = 5, then the output should be: 4 1
• If n < 1, output nothing.

The mathematical condition for a perfect square is given by \( i^2 \) where \( i \) is an integer and \( i^2 \leq n \). The algorithm should compute the integer part of \( \sqrt{n} \) and then generate the squares in descending order.

inputFormat

Input is given from stdin as a single integer n.

Constraints:

• n is an integer.

outputFormat

Output to stdout a sequence of perfect squares in descending order, separated by a single space. If there is no valid perfect square (i.e. n < 1), output nothing.

16

16 9 4 1