lightningrod.cpp: In function 'int main()':
lightningrod.cpp:17:25: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::stack<std::pair<int, int> >::size_type {aka long unsigned int}' [-Wformat=]
printf("%d",a.size());
~~~~~~~~^
lightningrod.cpp:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&n);
~~~~~^~~~~~~~~
lightningrod.cpp:13:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&x,&y);
~~~~~^~~~~~~~~~~~~~