# Count sources

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

The directed graph is given with the adjacency list. The vertex of directed graph is called a source if no edge comes into it. Count the number of sources in the graph.

## Input

First line contains the number of vertices n (1 ≤ n ≤ 100). The next i-th line contains the number of edges adjacent to the i-th vertex, and the vertex numbers where these edges go in increasing order.

## Output

Print the number of sources in the graph.

### Example

Graph contains 1 source - the vertex number 4.

## Examples

Input #1

Answer #1

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