125571
A mass call event or mass calling event ( also MCE in telephony usage ) is a situation in which an extraordinarily high number of telephone call s are attempted into or out of an area , causing tremendous network congestion , and therefore service which is either significantly degraded or potentially almost completely unavailable .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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