/in/foo.cc: In function 'int main()':
/in/foo.cc:11:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^
/in/foo.cc:12:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",s1+1);scanf("%s",s2+1);
                  ^
/in/foo.cc:12:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",s1+1);scanf("%s",s2+1);
                                   ^