Compilare: main.cpp: In function 'int main()': main.cpp:76:9: warning: unused variable 'm0' [-Wunused-variable] int m0=m; ^~ main.cpp:63:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("johnie.in","r",stdin); ^ main.cpp:64:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("johnie.out","w",stdout); ^ main.cpp:66:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ main.cpp:70:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^