/in/foo.cc: In function 'int main()':
/in/foo.cc:6:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
/in/foo.cc:9:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |   scanf("%d",&m);
      |   ~~~~~^~~~~~~~~
/in/foo.cc:12:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   12 |   for(int j=0;j<m;++j) scanf("%d",&a[i][j]);
      |                        ~~~~~^~~~~~~~~~~~~~~