import sys
input = sys.stdin.readline


def matmul(A, B):
    sz = len(A)
    res = [[0]*sz for _ in range(sz)]
    for i in range(sz):
        for j in range(sz):
            for k in range(sz):
                res[i][j] = max(res[i][j], A[i][k]+B[k][j])
    return res


N = int(input())
M = int(input())
A = list(list(map(int,input().split())) for _ in range(M))
D = N.bit_length()
mat = [-1]*D
mat[0] = A
for i in range(1, D):
    mat[i] = matmul(mat[i-1],mat[i-1])

dp = [0]*M
N -= 1
for d in reversed(range(D)):
    if (N>>d)&1:
        ndp = [0]*M
        for i in range(M):
            for j in range(M):
                ndp[j] = max(ndp[j], dp[i] + mat[d][i][j])
        dp = ndp
print(max(dp))