Hello, CodeChef community! 
Today, I learn two useful keywords in C++, tolower() and abs(). These functions are handy for manipulating characters and numbers, respectively, and come up often in competitive programming.
The tolower() function is part of the library in C++ and is used to convert an uppercase character to its lowercase form. If the character is already lowercase, it remains unchanged.
The abs() function is part of the library for integers and for floating-point numbers in C++. It returns the absolute (non-negative) value of a number.