I need to use a macro for a long formula but I keep getting a 1004 error when i try to use the Macro. The formula works fine when i enter it into a cell manually. When i click debug everything from "Selection.FormulaR1C1" to the end of the formula gets highlighted yellow.

Sub Macro1()
'
' Macro1 Macro
' aa
'
' Keyboard Shortcut: Ctrl+Shift+U
'
    Range(Selection, Selection.End(xlDown)).Select
    Selection.FormulaR1C1 = _
        "=SQRT((((SQRT((R2C[-81]-R2C[-72])^2+(R2C[-79]-R2C[-71])^2))+(SQRT((R2C[-81]-RC[-90])^2+(R2C[-79]-RC[-88])^2))+(SQRT((R2C[-72]-RC[-90])^2+(R2C[-71]-RC[-88])^2)))/2)*((((SQRT((R2C[-81]-R2C[-72])^2+(R2C[-79]-R2C[-71])^2))+ (SQRT((R2C[-81]-RC[-90])^2+(R2C[-79]-RC[-88])^2)) +(SQRT((R2C[-72]-RC[-90])^2+(R2C[-71]-RC[-88])^2)))/2) -(SQRT((R2C[-81]-R2C[-72])^2+(R2C[-79]-R2C[" & _
        "))*((((SQRT((R2C[-81]-R2C[-72])^2+(R2C[-79]-R2C[-71])^2)) +(SQRT((R2C[-81]-RC[-90])^2+(R2C[-79]-RC[-88])^2)) +(SQRT((R2C[-72]-RC[-90])^2+(R2C[-71]-RC[-88])^2)))/2) -(SQRT((R2C[-81]-RC[-90])^2+(R2C[-79]-RC[-88])^2)))*((( (SQRT((R2C[-81]-R2C[-72])^2+(R2C[-79]-R2C[-71])^2))+(SQRT((R2C[-81]-RC[-90])^2+(R2C[-79]-RC[-88])^2))+(SQRT((R2C[-72]-RC[-90])^2+(R2C[-71]-RC[-88])^" & _
        "SQRT((R2C[-72]-RC[-90])^2+(R2C[-71]-RC[-88])^2))))"
End Sub