def matmul(A,B): # A,B: 行列
    res = [[0]*len(B[0]) for _ in range(len(A))]
    for i, resi in enumerate(res):
        for k, aik in enumerate(A[i]):
            for j,bkj in enumerate(B[k]):
                resi[j] = max(resi[j],aik+bkj)
    return res

def matpow(A,p): #A^p mod M
    if p%2:
        return matmul(A, matpow(A,p-1))
    elif p > 0:
        b = matpow(A,p//2)
        return matmul(b,b)
    else:
        return [[0 if i == j else -(1<<31) for j in range(len(A))] for i in range(len(A))]

n = int(input())
m = int(input())
a = [list(map(int,input().split())) for _ in range(m)]
r = matmul([[0]*m],matpow(a,n-1))
print(max(r[0]))