Who can explained this meaning? I want know 2 and 3, where is that?

process.stdin.resume(); process.stdin.setEncoding('ascii');

var input_stdin = ""; var input_stdin_array = ""; var input_currentline = 0;

process.stdin.on('data', function (data) { input_stdin += data; });

process.stdin.on('end', function () { input_stdin_array = input_stdin.split("\n"); main();
});

function readLine() { return input_stdin_array[input_currentline++]; }

function solveMeFirst(a, b) { // Hint: Type return a+b below
return a+b; }

function main() { var a = parseInt(readLine()); var b = parseInt(readLine());;

var res = solveMeFirst(a, b);
console.log(res);

}