from copy import deepcopy
n,m = map(int,input().split())
A = [list(map(int,input().split())) for i in range(n)]

ans = 10**10
for i in range(1<<(n+2)):

    s = deepcopy(A)
    count = 0
    c = 0
    for j in range(n+2):
        if i >> j & 1:
            c += 1
            if j == n:
                for k in range(n):
                    count += s[k][k]
                    s[k][k] = 0
            elif j == n+1:
                for k in range(n):
                    count += s[k][-1-k]
                    s[k][-1-k] = 0
            else:
                for k in range(n):
                    count += s[k][j]
                    s[k][j] = 0
    l = [sum(s[i]) for i in range(n)]
    l.sort()
    now = 0
    if c+n < m:
        continue
    while c < m:
        c += 1
        count += l[now]
        now += 1
    ans = min(ans,count)

print(ans)