{"raw_statement":[{"iden":"problem statement","content":"Find the number of ways to choose a pair of an even number and an odd number from the positive integers between $1$ and $K$ (inclusive). The order does not matter."},{"iden":"constraints","content":"*   $2\\leq K\\leq 100$\n*   $K$ is an integer."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$K$"},{"iden":"sample input 1","content":"3"},{"iden":"sample output 1","content":"2\n\nTwo pairs can be chosen: $(2,1)$ and $(2,3)$."},{"iden":"sample input 2","content":"6"},{"iden":"sample output 2","content":"9"},{"iden":"sample input 3","content":"11"},{"iden":"sample output 3","content":"30"},{"iden":"sample input 4","content":"50"},{"iden":"sample output 4","content":"625"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}