According to Wiki, George Mallory’s famous reply to the question why he wanted to climb Mount Everest (“Because it’s there”) has been called “the most famous three words in mountaineering”. Similarly, Ronald Reagan has said that the nine most terrifying words in the English langauge were “I’m from the government, and I’m here to help”.
In both cases, the word count works out only if the contractions “it’s” and “I’m” count as one word each. Is that established and uncontroversial? I would find it logical to argue that these contractions are mere simplifications of the pronunciation of a two-word phrase, but that grammatically they remain two words and should thus be counted as such.