foo.cc: In function 'int main()':
foo.cc:38:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   38 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
foo.cc:41:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   41 |   int x,son;scanf("%d",&x);
      |             ~~~~~^~~~~~~~~
foo.cc:42:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   42 |   scanf("%lld%d",&cost[x],&son);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:46:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   46 |    int v;scanf("%d",&v);
      |          ~~~~~^~~~~~~~~

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