function solve(params){
    params.pop();
    let stores = {};
    let itemsArray = [];

    for ( let param of params){
        let tokens = param.split('->');
        let command = tokens[0];
        let store = tokens[1];
        let items = tokens[2];

        if(command === "Add") {
            if (items.includes(',')) {
                let splittedItems = items.split(',');
                if(!stores.hasOwnProperty(store)){
                    stores[store] = splittedItems;
                }else{
                    for ( let ele of splittedItems){
                        stores[store].push(ele);
                    }
                }
            }else{
                if(!stores.hasOwnProperty(store)){
                    stores[store] = [items];
                }else{
                    stores[store].push(items);
                }
            }
        }
        else if(command === "Remove"){
            if(stores.hasOwnProperty(store)){
                delete stores[store];
            }
        }
    }

    console.log("Stores list:");
    let sortedStores = Object.entries(stores)
        .sort((a,b)=>{
            return b[1].length - a[1].length || b[0].localeCompare([a[0]])
        })
        .forEach(e=>{
            console.log(`${e[0]}`);
            for ( let item of e[1]){
                console.log(`<<${item}>>`);
            }
        });

}
solve(["Add->PeakSports->Map,Navigation,Compass",
"Add->Paragon->Sunscreen" ,
"Add->Groceries->Dried-fruit,Nuts" ,
"Add->Groceries->Nuts" ,
"Add->Paragon->Tent" ,
"Remove->Paragon" ,
"Add->Pharmacy->Pain-killers" ,
"END"]);