# Challenge 3: Calculate the Number of Nodes in a Given Graph Level

Given a graph, calculate the number of nodes in an undirected graph level.

## We'll cover the following

## Problem Statement

Implement a function that returns the number of nodes at a given level of an **undirected** graph in C++.

Try modifying the

Breadth-First Traversalalgorithm to achieve this goal.

To solve this problem, all the previously implemented data structures will be available to us.

### Input

An undirected graph represented as an adjacency list, a starting vertex, and the level whose number of nodes we need to find.

### Output

The number of nodes returned as a simple integer.

### Sample Input

**Graph:**

```
graph {0 - 1
0 - 2
1 - 3
2 - 3
3 - 5
2 - 4
}
```

**Level:** 1

### Sample Output

```
1
```

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