black, grey, white = range(3)
def dfs(colors, adj_matrix, v):
colors[v] = grey
for w, edge in enumerate(adj_matrix[v]):
if (edge == 1) and (colors[w] == white):
dfs(colors, adj_matrix, w)
colors[v] = black
n, s = map(int, input().split())
s -= 1
adj_matrix = [map(int, input().split()) for j in range(n)]
colors = [white for i in range(n)]
dfs(colors, adj_matrix, s)
print(colors.count(black))
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