radio.onReceivedNumber(function (receivedNumber) {
    basic.showIcon(IconNames.Yes)
    basic.showNumber(receivedNumber)
    ack = 1
})
let ack = 0
radio.setGroup(1)
basic.showIcon(IconNames.Heart)
basic.forever(function () {
    if (ack == 1) {
        radio.sendString("OK")
        basic.showIcon(IconNames.Happy)
        basic.pause(1000)
        ack = 0
    }
})