> For the complete documentation index, see [llms.txt](https://garychang.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://garychang.gitbook.io/leetcode/untitled-1.md).

# 67. Add Binary

<https://leetcode.com/problems/add-binary>[/description/](https://leetcode.com/problems/climbing-stairs/description/)

Given two binary strings, return their sum (also a binary string).

The input strings are both **non-empty** and contains only characters `1` or `0`.

**Example 1:**

```
Input: a = "11", b = "1"
Output: "100"
```

**Example 2:**

```
Input: a = "1010", b = "1011"
Output: "10101"
```

**Solution:**

```
class Solution(object):
    def addBinary(self, a, b):
        """
        :type a: str
        :type b: str
        :rtype: str
        """
        return bin(int(a, 2) + int(b, 2))[2:]
```