# 45: Minimum depth of a binary tree

Given a `binary tree`

. Find a `minimum depth`

of the binary tree

Note: The

`minimum depth`

is the number of nodes from the root node to the nearest leaf node

`Example 1`

```
Input: 1
/ \
2 3
/ \
6 7
Output: 2
```

Explanation:

`1 -> 2`

`Example 2`

```
Input: 1
\
3
Output: 2
```