foo.cc: In function 'void dfs(int)':
foo.cc:32:24: warning: 'a' may be used uninitialized [-Wmaybe-uninitialized]
   32 |                 while(x!=a)
      |                       ~^~~
foo.cc:31:21: note: 'a' was declared here
   31 |                 int a;
      |                     ^

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