#include <iostream>
#include <stdexcept>

class RoundLoad {
    int capacity_;
public:
    RoundLoad() : RoundLoad(10) {}
    explicit RoundLoad(int capacity) : capacity_{capacity} {
        if (capacity <= 0 || capacity > 1000) { throw std::invalid_argument{"capacity"}; }
    }
    int capacity() const { return capacity_; }
};

int main() {
    RoundLoad standard;
    RoundLoad compact{4};
    std::cout << "Capacities: " << standard.capacity() << ' ' << compact.capacity() << '\n';
}