A Very Important Example Of Pigeonhole Principle

graph TB A["A very important Example of Pigeonhole Principle"] A --> B["Definition"] A --> C["Examples"] B --> D["Pigeonhole Principle"] D --> E["If n items are put into m containers and n > m, then at least one container must contain more than one item"] C --> F["Example 1"] C --> G["Example 2"] F --> H["If 13 shoes are in a box that can only contain 12 shoes, then at least one box must contain more than one shoe"] G --> I["If 5 people are in a room and there are only 4 chairs, then at least one person must be standing"]