Obhod

n, s = map(int, input().split())
g = []
for i in range(n):
    g.append(list(map(int, input().split())))



def dfs(node, visited=[0]*100):
    if visited[node-1]:
        return 0
    else:
        visited[node-1] = 1
        subnodes = 0
        for i, n in enumerate(g[node-1]):
            if n:
                subnodes += dfs(i+1, visited)
        return 1 + subnodes

print(dfs(s))