n, m = map(int, input().split())

lst = [[int(x) for x in input().split()] for _ in range(n)]

k, row = int(input()), []

for i in range(n):

   count = 0

   for j in range(m):

       if lst[i][j] == 0:

           count += 1

       if count == k:

           row.append(i + 1)

       if lst[i][j] == 1:

           count = 0

print(min(row, default=0))