foo.cc: In function 'int main()':
foo.cc:5:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d\n",&raws,&lines);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:7:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
foo.cc:8:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     if(i%lines==0) scanf("\n");
                    ~~~~~^~~~~~

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