Main.cpp:12:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
12 | main(){
| ^~~~
Main.cpp: In function 'int main()':
Main.cpp:26:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | for(int j = 1; j < v[i].size(); j++) {
| ~~^~~~~~~~~~~~~
Main.cpp:33:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
33 | for(int j = 0; j < v[i].size(); j++) s.insert(v[i][j]);
| ~~^~~~~~~~~~~~~