N = int(input())
M = int(input())

X = [list(map(int, input().split(' '))) for _ in range(M)]
A = [[[0 for _ in range(M+1)] for _ in range(M+1)] for _ in range(M+2)]

for i in range(M):
    for j in range(M):
        A[0][i][j] = X[i][j]

for i in range(M+1):
    for x in range(M):
        for y in range(M):
            for z in range(M):
                A[i+1][x][y] = max(A[i+1][x][y], A[i][x][z]+A[i][z][y])

B = [[[0 for _ in range(M+1)] for _ in range(M+1)] for _ in range(M+2)]
answer = 0                
N = N-1
for i in range(M+1):
    if N & (1<<i):
        for x in range(M):
            for y in range(M):
                for z in range(M):
                    B[i+1][x][y] = max(B[i+1][x][y], B[i][x][z]+A[i][z][y])
                    answer = max(answer, B[i+1][x][y])
    else:
        for x in range(M):
            for y in range(M):
                B[i+1][x][y] = B[i][x][y] 

print(answer)