L
A; Z; C; X; F; U; J; Q; O; ? If translate to letters' sequence numbers we get: 1,26, 3 (+2), 24 (-2), 6 (+5), 21 (-5), 10 (+9), 17 (-9), 15 (+14), 12 (-14) = L
If symbols of alphabets (without any change in their sense and meaning) are L M V A K B N C P I D Y O S E Q R F T H G J U W Z X then How we will write "WORLDCUP".