Compilare: main.cpp: In function 'int main()': main.cpp:20:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=s.size();i++){ ~^~~~~~~~~~ main.cpp:30:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=s.size();i++) ~^~~~~~~~~~ main.cpp:31:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(phi[i]==a.size()) ~~~~~~^~~~~~~~~~