n,k = map(int,input().split()) xy = [tuple(map(int,input().split())) for _ in range(n)]+[(0,0)] dp = [[[10**18]*(k+1) for _ in range(n+1)] for _ in range(1<<n)] dp[0][n][k] = 0 for s in range(1<<n): for i in range(n+1): if i<n and s>>i&1==0: continue xi,yi = xy[i] for j in range(n+1): xj,yj = xy[j]; d = ((xi-xj)**2+(yi-yj)**2)**0.5 if j<n: if s>>j&1==1: continue for l in range(k): t = s^1<<j dp[t][j][l] = min(dp[t][j][l],dp[s][i][l+1]+d) else: for l in range(k): dp[s][j][k] = min(dp[s][j][k],dp[s][i][l]+d) print(dp[-1][-1][-1])