Compilare: main.cpp: In function 'int main()': main.cpp:36:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(st.size()>m) ~~~~~~~~~^~ main.cpp:29:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.in","r",stdin); ^ main.cpp:30:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.out","w",stdout); ^ main.cpp:32:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n,&m); ^ main.cpp:34:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &c); ^