foo.cc: In function 'int main()':
foo.cc:8:3: warning: statement has no effect [-Wunused-value]
  m<n;
  ~^~
foo.cc:27:14: warning: 'Sn' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if(Sm==m+n+1&&Sn==m+n+1&&Sm==Sn)
     ~~~~~~~~~^~~~~~~~~~~
foo.cc:27:2: warning: 'Sm' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if(Sm==m+n+1&&Sn==m+n+1&&Sm==Sn)
  ^~

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