x = input()
x = x.split(' ')
print(int(x[0])//2)969. Pancake Sorting | 967. Numbers With Same Consecutive Differences |
957. Prison Cells After N Days | 946. Validate Stack Sequences |
921. Minimum Add to Make Parentheses Valid | 881. Boats to Save People |
497. Random Point in Non-overlapping Rectangles | 528. Random Pick with Weight |
470. Implement Rand10() Using Rand7() | 866. Prime Palindrome |
1516A - Tit for Tat | 622. Design Circular Queue |
814. Binary Tree Pruning | 791. Custom Sort String |
787. Cheapest Flights Within K Stops | 779. K-th Symbol in Grammar |
701. Insert into a Binary Search Tree | 429. N-ary Tree Level Order Traversal |
739. Daily Temperatures | 647. Palindromic Substrings |
583. Delete Operation for Two Strings | 518. Coin Change 2 |
516. Longest Palindromic Subsequence | 468. Validate IP Address |
450. Delete Node in a BST | 445. Add Two Numbers II |
442. Find All Duplicates in an Array | 437. Path Sum III |
436. Find Right Interval | 435. Non-overlapping Intervals |