var maximumUnits = function (box, truck) {
let maxBoxs = boxTypes.sort((a, b) => (b[1] - a[1]))
let count = 0;
for(let i -= 0;i < maxBoxs.length;i++) {
const [a, b] = maxBoxs[i]
if(truck === 0) {
return count
}else if (truck >= a) {
count += a * b
truck -= a
}else if (truck <= a) {
count += truck * b
truck = 0;
}
}
return count
}