Compilare: main.cpp: In function 'void solve()': main.cpp:43:10: warning: comparison of integer expressions of different signedness: 'lo' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 43 | if(a <= s.size()) | ~~^~~~~~~~~~~ main.cpp:77:21: warning: comparison of integer expressions of different signedness: 'std::stack<char>::size_type' {aka 'long unsigned int'} and 'lo' {aka 'long long int'} [-Wsign-compare] 77 | while(st.size() != a) | ~~~~~~~~~~^~~~