int main() { f(0); return 0; }
Standard input is empty
ABCDEFGHIJKLMNOPQRSTUVWXYZ BBCDEFGHIJKLMNOPQRSTUVWXYZ CCCDEFGHIJKLMNOPQRSTUVWXYZ DDDDEFGHIJKLMNOPQRSTUVWXYZ EEEEEFGHIJKLMNOPQRSTUVWXYZ FFFFFFGHIJKLMNOPQRSTUVWXYZ GGGGGGGHIJKLMNOPQRSTUVWXYZ HHHHHHHHIJKLMNOPQRSTUVWXYZ IIIIIIIIIJKLMNOPQRSTUVWXYZ JJJJJJJJJJKLMNOPQRSTUVWXYZ KKKKKKKKKKKLMNOPQRSTUVWXYZ LLLLLLLLLLLLMNOPQRSTUVWXYZ MMMMMMMMMMMMMNOPQRSTUVWXYZ NNNNNNNNNNNNNNOPQRSTUVWXYZ OOOOOOOOOOOOOOOPQRSTUVWXYZ PPPPPPPPPPPPPPPPQRSTUVWXYZ QQQQQQQQQQQQQQQQQRSTUVWXYZ RRRRRRRRRRRRRRRRRRSTUVWXYZ SSSSSSSSSSSSSSSSSSSTUVWXYZ TTTTTTTTTTTTTTTTTTTTUVWXYZ UUUUUUUUUUUUUUUUUUUUUVWXYZ VVVVVVVVVVVVVVVVVVVVVVWXYZ WWWWWWWWWWWWWWWWWWWWWWWXYZ XXXXXXXXXXXXXXXXXXXXXXXXYZ YYYYYYYYYYYYYYYYYYYYYYYYYZ ZZZZZZZZZZZZZZZZZZZZZZZZZZ