Re^2: RegEx + vs. {1,}

[choroba]

Or, just remove the comma from the quantifier: \w{2}

[tobyink]

Indeed. There can never be a three character sequence in your string which occurs more frequently than a two character sequence. (Because the three character sequence contains two two character sequences.)

[grizzley]

But what should be returned if we have string 'abcabcabcdef' with same amount of three-chars-long and two-chars-long string? 'ab' or 'abc'? I assume OP wants the longer one.