function catalogue(input) {
    let catalog = [];

    for (let i = 0; i < input.length; i ++) {
        let currItem = input[i].split(" : ");
        let newItem = {};
        newItem.initial = currItem[0][0];
        newItem.productName =  currItem[0];
        newItem.productPrice = currItem[1];
        catalog.push(newItem);
    }

    catalog.sort((a, b) => {
        if (a.productName > b.productName) {
            return 1
        } else {
            return -1
        }
    });

    let initList = [];
    for (let item in catalog) {
        if (initList.includes(catalog[item].initial)) {
            console.log(`  ${catalog[item].productName}: ${catalog[item].productPrice}`);
        } else {
            console.log(`${catalog[item].initial}`);
            console.log(`  ${catalog[item].productName}: ${catalog[item].productPrice}`);
            initList.push(catalog[item].initial);
        }

    }


}