from itertools import product
n = int(input())-1
m = int(input())
M = list(range(m))
A = [list(map(int, input().split())) for _ in M]

# nを二進展開(n = sum([2**b for b in B]))
B = []
e = 0
while n != 0:
    if (n ^ 1<<e) < n:
        B.append(e)
        n ^= 1<<e
    e += 1

# DP[i][j][z] = iからjへ2**zで移動するときの最大利潤
DP = [[[0 for z in range(B[-1]+1)] for j in M] for i in M]
for z in range(B[-1]+1):
    for i, j in product(M, M):
        if z == 0:
            DP[i][j][z] = A[i][j]
        else:
            DP[i][j][z] = max([DP[i][k][z-1] + DP[k][j][z-1] for k in M])

# DQ[i][j] = iからjへ移動するときの最大利潤
for z, b in enumerate(B):
    if z == 0:
        DQ = [[DP[i][j][b] for j in M] for i in M]
    else:
        DQ = [[max([DQ[i][k] + DP[k][j][b] for k in M]) for j in M] for i in M]

print(max([DQ[i][j] for i, j in product(M, M)]))