N,K=map(int, input().split())
A=[(0,0)]
D=[[0]*(N+1) for _ in range(N+1)]

for i in range(N):
  x,y=map(int, input().split())
  A.append((x,y))
  
for i in range(N+1):
  for j in range(N+1):
    x,y=A[i]
    xx,yy=A[j]
    D[i][j]=((x-xx)**2+(y-yy)**2)**.5


dp=[[[10**18]*(1<<N) for _ in range(K+1)] for i in range(N+1)]
from collections import deque
d=deque()
dp[0][K][0]=0

for bit in range(1<<N):
  for k in range(0,K+1): 
    for pre in range(N+1):
      if dp[pre][k][bit]==10**18:
        continue
      for nex in range(1,N+1):
        nxt=nex-1
        if (bit>>nxt)&1==0:
          if k!=0:
            dp[nex][k-1][bit|(1<<nxt)]=min(dp[nex][k-1][bit|(1<<nxt)],dp[pre][k][bit]+D[pre][nex])
            dp[0][K][bit|(1<<nxt)]=min(dp[0][K][bit|(1<<nxt)],dp[pre][k][bit]+D[pre][nxt+1]+D[nex][0])
  
c=dp[0][K][-1]
print(c)