int input int for in input split for in range list map int input split

a = int(input())
k = 0
A = [[int(j) for j in input().split()] for i in range(a)]
b = list(map(int, input().split()))
for i in range(len(b)-1):
    if (A[b[i]-1][b[i+1]-1] == 0):
        k = 0
        break
    k+=A[b[i]-1][b[i+1]-1]
    
print(k)