// io/summain.cpp
#include <iostream>
#include <cstdlib>

namespace MyLib {
    double readAndProcessSum (std::istream&);
}
int main()
{
    using namespace std;
    double sum;

    try {
        sum = MyLib::readAndProcessSum(cin);
    }
    catch (const ios::failure& error) {
        cerr << "I/O exception: " << error.what() << endl;
        return EXIT_FAILURE;
    }
    catch (const exception& error) {
        cerr << "standard exception: " << error.what() << endl;
        return EXIT_FAILURE;
    }
    catch (...) {
        cerr << "unknown exception" << endl;
        return EXIT_FAILURE;
    }

    // Вывод суммы
    cout << "sum: " << sum << endl;
}