foo.cc: In function 'int main()':
foo.cc:31:17: warning: unused variable 't' [-Wunused-variable]
  int a1, n1, k, t = 0;
                 ^
foo.cc:35:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d", &a1, &n1, &k);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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