题目描述
Problem Description
There are $ n $ white stones arranged in a straight line with equal intervals. The distance between adjacent stones is $ 1 $.
Two players play a game with these stones. Each player, on their turn, selects one white stone and turns it black. However, a player cannot choose a stone that is within a distance of $ k $ from the stone that turned black in the previous turn.
The player who cannot choose a white stone first loses the game.
Determine which player, the first or the second, wins when both play optimally.
Input Format
The input is given in the following format:
$ n $ $ k $
- The first line contains an integer $ n $ ($1 \leq n \leq 50$), representing the number of stones, and an integer $ k $ ($0 \leq k \leq n$), representing the forbidden distance.
Output Format
Output first if the first player wins, or second if the second player wins, in one line.
End with a newline and do not include any extra characters or blank lines.
Sample Input and Output
Sample Input #1
2 1
Sample Output #1
first
Sample Input #2
3 0
Sample Output #2
first
Notes/Hints
Sample Explanation 1
Regardless of which stone is chosen, the other stone cannot be chosen on the next turn, so the first player wins.
Sample Explanation 2
Regardless of the order in which the stones are chosen, all three stones will turn black, so the first player wins.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分