foo.cc: In function 'int main()':
foo.cc:17:24: warning: operation on 'j' may be undefined [-Wsequence-point]
   17 |                 int j=j=n-i*3+1;
      |                       ~^~~~~~~~
foo.cc:14:19: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   14 |         long long ans;
      |                   ^~~

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