foo.cc: In function 'bool input()':
foo.cc:44:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d%d%d",&N,&M,&K);
 ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:51:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d%d%d",&a,&b,&c);
 ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc: In function 'int solve_aux_3()':
foo.cc:149:8: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
 return ans;
        ^~~
foo.cc: In function 'int solve_aux_2()':
foo.cc:212:8: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
 return ans;
        ^~~

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