/in/foo.cc: In function 'int main()':
/in/foo.cc:9:43: warning: too many arguments for format [-Wformat-extra-args]
     uint64_t a,b;scanf(SCNu64 SCNu64,&a,&b);
                                           ^
/in/foo.cc:10:24: error: expected ')' before ';' token
  printf(PRIu64,gcd(a,b);
                        ^