#include <iostream>
#include <vector>

int main() {
	for(auto values = [] (size_t index) -> int& { 
		    static std::vector<int> values(2, 0); 
		    return values[index]; 
		}; values(0) != 5; ++values(0)) {
		std::cout << values(0) << ": " << (values(1) += 2) << std::endl;
	}
	return 0;
}