house party

function  solve(arr){

    let list = [];

    for (let i = 0; i < arr.length; i++) {

        let command = arr[i].split(' ');

        if (command.length == 3){

            let name = command[0];

            if (list.includes(name)){
                console.log(`${name} is already in the list!`);
            }
            else{
                list.push(name);
            }

        } else {

            let name = command[0];

            if (list.includes(name)){
                let index = list.indexOf(name);
                list.splice(index, 1);
            }
            else{
                console.log(`${name} is not in the list!`)
            }
        }
    }

    for (const el of list) {
        console.log(el);
    }

}