foo.cc: In function ‘int judge(int)’:
foo.cc:6:13: warning: unused variable ‘m’ [-Wunused-variable]
    6 |         int m=sqrt(k);
      |             ^
foo.cc: In function ‘int main()’:
foo.cc:15:13: warning: unused variable ‘ans’ [-Wunused-variable]
   15 |         int ans=0;
      |             ^~~