class Solution {
public:
    int maximumUnits(vector<vector<int>>& boxTypes, int truckSize) {
        sort(boxTypes.begin(),boxTypes.end(),
             [](auto& a,auto& b){return a[1] > b[1];});
        int ans = 0;
        for(auto& e : boxTypes)
        {
            ans += e[1] * min(truckSize,e[0]);
            truckSize -= e[0];
            if(truckSize <= 0)
            break;
        }

        return ans;
    }
};