/in/foo.cc: In function 'int main()':
/in/foo.cc:9:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
/in/foo.cc:12:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s%d%s",&s1[1],&k,&s2[1]);
                                   ^