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4 of 4 added 87 characters in body

Bash +GNU date, 72 73 bytes

for((d=0;1`date +%d%m -d$d\day`-12512;d++));{ x+=\ Eve;};echo Christmas$x
  • one byte saved replacing != with -
  • another removing extra space
  • fix -3 bytes d=0, because date -dday is date+1 and doesn't work on 25/12

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