function solve(input){
    let airport = new Map();
    let leftPlanes = new Set();
    for(let request of input){
        // console.log(airport)
        let [id, town, passengers, action] = request.split(' ')
        passengers = Number(passengers)
        if(action == 'land'){
            if(!leftPlanes.has(id)){
                leftPlanes.add(id);
                if(!airport.has(town)){
                    let obj = {'arrivals': passengers, 'departures': 0, planes: new Set()};
                    obj['planes'].add(id);
                    airport.set(town, obj);
                }
                else{
                    airport.get(town)['arrivals'] += passengers;
                    airport.get(town)['planes'].add(id);
                }
            }

        }
        else if(action=='depart'){
            if(leftPlanes.has(id)){
                leftPlanes.delete(id);
                if(airport.has(town)){
                    airport.get(town)['departures'] += passengers;
                    airport.get(town)['planes'].add(id);
                }
                else{
                    let obj = {'arrivals': 0, 'departures': passengers, planes: new Set()};
                    obj['planes'].add(id);
                    airport.set(town, obj);
                }
            }
        }

    }

    let leftPlanesArr = Array.from(leftPlanes)
    leftPlanesArr.sort(function (a, b) {
        if (a.toUpperCase() < b.toUpperCase()) {
            return -1;
        }
        if (a.toUpperCase() > b.toUpperCase()) {
            return 1;
        }
        return 0;
    })
    console.log("Planes left:")
    for(let plane of leftPlanesArr){
        console.log("- " + plane)
    }

    let airportArr = Array.from(airport)
    airportArr.sort(function (a, b) {
        if (a[1]['arrivals'] < b[1]['arrivals']) //sort arrivals descending
            return 1;
        if (a[1]['arrivals'] > b[1]['arrivals'])
            return -1;

        if (a[0].toUpperCase() > b[0].toUpperCase()) {
            return -1;
        }
        if (a[0].toUpperCase() < b[0].toUpperCase()) {
            return 1;
        }
        return 0;
    });

    for(let array of airportArr){
        let townName = array[0];
        console.log(townName);
        let arrivals = array[1]['arrivals'];
        let departures = array[1]['departures'];
        console.log("Arrivals: " + arrivals);;
        console.log('Departures: ' + departures);
        let planesInTown = array[1]['planes'];
        let planesArr = Array.from(planesInTown);
        planesArr.sort(function (a, b) {
            if (a.toUpperCase() < b.toUpperCase()) {
                return -1;
            }
            if (a.toUpperCase() > b.toUpperCase()) {
                return 1;
            }
            return 0;
        })
        console.log("Planes:")
        for(let plane of planesArr){
            console.log("-- " + plane)
        }
    }

}