INF = 10 ** 9
MOD = 10 **9 + 7
import sys
sys.setrecursionlimit(100000000)
dy = (-1,0,1,0)
dx = (0,1,0,-1)
from  collections import deque
from math import factorial

def main():
    n,k = map(int,input().split())
    print(n/2)
if __name__=='__main__':
    main()