8#define __GCC_VERSION__ (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) 
    9#if __cplusplus <= 201703L || (_MSC_VER && _MSC_VER < 1929) || (!__clang__ && !_MSC_VER && __GCC_VERSION__ < 100000) 
   12    using days = std::chrono::duration<long, std::ratio<86400>>;
 
   13    using weeks = std::chrono::duration<long, std::ratio<604800>>;
 
   14    using months = std::chrono::duration<long, std::ratio<2629746>>;
 
   15    using years = std::chrono::duration<long, std::ratio<31556952>>;