foo.cc: In function 'int main()':
foo.cc:52:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
foo.cc:53:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (int i = 0; i <= n; ++i) scanf("%d", a + i);
                                  ~~~~~^~~~~~~~~~~~~
foo.cc:54:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (int i = 0; i <= m; ++i) scanf("%d", b + i);
                                  ~~~~~^~~~~~~~~~~~~

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