foo.cc: In function 'int main()':
foo.cc:79:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf( "%d%d" , &n , &m ) ;
 ~~~~~^~~~~~~~~~~~~~~~~~~~
foo.cc:84:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 int x ; scanf( "%d" , &x ) ;
         ~~~~~^~~~~~~~~~~~~
foo.cc:91:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 int x ; scanf( "%d" , &x ) ;
         ~~~~~^~~~~~~~~~~~~

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