import sys
input = sys.stdin.readline

n=int(input())
m=int(input())

A=[list(map(int,input().split())) for i in range(m)]

DP=[A]

for tests in range(32):
    X=DP[-1]

    Y=[[0]*m for i in range(m)]

    for i in range(m):
        for j in range(m):
            for k in range(m):
                Y[i][j]=max(Y[i][j],X[i][k]+X[k][j])

    DP.append(Y)

NOW=[[0]*m for i in range(m)]

n-=1
for b in range(31,-1,-1):
    if n>=(1<<b):

        n-=(1<<b)

        Y=[[0]*m for i in range(m)]

        for i in range(m):
            for j in range(m):
                for k in range(m):
                    Y[i][j]=max(Y[i][j],NOW[i][k]+DP[b][k][j])
        NOW=Y

ANS=0
for i in range(m):
    ANS=max(ANS,max(NOW[i]))

print(ANS)