#include <iostream>
#include <vector>

int main()
{
    std::vector<int> nums { 1, 2, 3, 4, 5 };

    auto sum = 0;
    for (auto i = 0; i <= static_cast<int>(nums.size()); ++i) {
        sum += i;
    }

    std::cout << sum << "\n";
}