foo.cc: In function 'bool hw(long long int)':
foo.cc:14:20: warning: unused variable 'j' [-Wunused-variable]
   14 |  long long k,len=0,j;
      |                    ^
foo.cc: In function 'int main()':
foo.cc:35:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   35 |  scanf("%lld%lld",&a,&b);
      |  ~~~~~^~~~~~~~~~~~~~~~~~

Found 10 testcases.
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