function shopping_list(data) {
    let products = data.shift().split("!")

    let counter = 0
    while (true) {
        if (data[counter] === 'Go Shopping!') {
            console.log(products.join(', '))
            break
        }

        let command_data = data[counter].split(' ')
        let command = command_data[0]

        if (command === 'Urgent') {
            let current_item = command_data[1]
            if (!products.includes(current_item)) {
                products.unshift(current_item)
                }
            } else if (command === 'Unnecessary') {
                 let elementToRemove = command_data[1]
                 if (products.includes(elementToRemove)) {
                     let index = products.indexOf(elementToRemove)
                     products.splice(index, 1)
                 }
            } else if (command === 'Correct') {
                 let old_item = command_data[1]
                 let new_item = command_data[2]
                 if (products.includes(old_item)) {
                     let index = products.indexOf(old_item)
                     products.splice(index, 1, new_item)
                 }
            } else if (command === 'Rearrange ') {
                let rearrange_item = command_data[1]
                if(products.includes(rearrange_item)) {
                let index = products.indexOf(rearrange_item);
                products.splice(index, 1);
                products.push(rearrange_item);
                }
            }
        counter += 1
    }
}