function solve(input) {

    let str = input.shift()

    const actions = { "Add Stop": addStop, "Remove Stop": remove, Switch: switched }



    function addStop(index, newPart) {

        if (str[index] !== undefined) {             //here

            index = Number(index)

            let firstPart = str.substring(0, index);

            let secondPart = str.substring(index);

            str = firstPart + newPart + secondPart;

        }

        console.log(str)

    }

    function remove(startIndex, endIndex) {

        startIndex = Number(startIndex);

        endIndex = Number(endIndex);

        if (str[startIndex] !== undefined && str[endIndex] !== undefined) {         //here

            let cut = str.substring(startIndex, endIndex + 1);

            str = str.replace(cut, "")

        }

        console.log(str)

    }

    function switched(oldItem, newItem) {

        //if (str.includes(oldItem)) {
        //
        //    while (str.includes(oldItem)) {
        //
        //        str = str.replace(oldItem, newItem)
        //
        //    }
        //
        //}
        if (str.includes(oldItem)) {                        //here
            str = str.split(oldItem).join(newItem);         //here
        }                                                   //here

        console.log(str)

    }

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

        let [command, a, b] = input[i].split(":")

        if (input[i] === "Travel") break

        actions[command](a, b)

    }

    console.log(`Ready for world tour! Planned stops: ${str}`)

}