If ElseIf in Robot Framework

I want get value from Keyword By use else if.

example

String text = ""  
If variable > 5
   text = "one";
else if variable <5
   text = "two";
else
   text = "three";

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In Robot Framework

I use code.

${txt}    Set Variable
${txt}=    Run Keyword If    ${lenght} > 5    Some Keyword
\    ELSE IF    ${lenght} < 5    Some Keyword
\    ELSE    Some Keyword
Log       ${txt}

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EROR !!

In Keyword ELSE IF  ;  Keyword name cannot be empty