foo.cc: In function 'int main()':
foo.cc:24:15: warning: format '%lu' expects argument of type 'long unsigned int', but argument 2 has type 'long long unsigned int' [-Wformat=]
   24 |     printf("%lu\n" ,ans);
      |             ~~^     ~~~
      |               |     |
      |               |     long long unsigned int
      |               long unsigned int
      |             %llu
foo.cc:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
foo.cc:11:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |      for (int j = 1; j <= m; j++) scanf("%d", &a[i][j]);
      |                                   ~~~~~^~~~~~~~~~~~~~~~

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