foo.cc: In function 'int main()':
foo.cc:21:8: warning: unused variable 'j' [-Wunused-variable]
  ll i, j, n, m;
        ^
foo.cc:21:14: warning: unused variable 'm' [-Wunused-variable]
  ll i, j, n, m;
              ^
foo.cc:22:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld", &n);
  ~~~~~^~~~~~~~~~~~
foo.cc:24:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld %lld", &p[i], &a[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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