608 B | 608 chars
import sys
from math import sqrt, pi, sin, factorial
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = " " : [*map(int,inp().split(x))]
mfi = lambda x = " " : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
def solve():
n, k = mii()
d1 = [i for i in range(1, n // 2 + 1)]
d2 = [i for i in range(n - 1, n // 2, -1)]
for _ in range(k - 1):
d2.append(d1.pop())
d1 = [d2.pop(0)] + d1
d2 = [n] + d2
for i in range(n // 2):
print(f"{d1[i]}-{d2[i]}")
if __name__ == "__main__":
tc = 1
for t in range(tc):
solve()