View Compilation Error

0_0_39119915_10857.cpp:20:13: error: 'uint64_t' does not name a type
   20 | using u64 = uint64_t;
      |             ^~~~~~~~
0_0_39119915_10857.cpp:16:1: note: 'uint64_t' is defined in header '<cstdint>'; did you forget to '#include <cstdint>'?
   15 | #include <iomanip>
  +++ |+#include <cstdint>
   16 |