1360\. Number of Days Between Two Dates

Easy

Write a program to count the number of days between two dates.

The two dates are given as strings, their format is `YYYY-MM-DD` as shown in the examples.

**Example 1:**

**Input:** date1 = "2019-06-29", date2 = "2019-06-30"

**Output:** 1

**Example 2:**

**Input:** date1 = "2020-01-15", date2 = "2019-12-31"

**Output:** 15

**Constraints:**

*   The given dates are valid dates between the years `1971` and `2100`.