Compilare: main.c: In function 'main': main.c:14:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("nrcuv.in","r",stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:15:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("nrcuv.out","w",stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:16:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~ main.c:19:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%c%c", &a,&b); ^~~~~~~~~~~~~~~~~~~~