# Should be easy to you!

$$({ 2 }^{ 2 }-{ 2 }^{ 2-1 })({ 3 }^{ 3 }-{ 3 }^{ 3-1 })({ 4 }^{ 4 }-{ 4 }^{ 4-1 })({ 5 }^{ 5 }-{ 5 }^{ 5-1 })({ 6 }^{ 6 }-{ 6 }^{ 6-1 })({ 7 }^{ 7 }-{ 7 }^{ 7-1 })({ 8 }^{ 8 }-{ 8 }^{ 8-1 })({ 9 }^{ 9 }-{ 9 }^{ 9-1 })$$

If the expression above simplifies to $${ 2 }^{ a }{ 3 }^{ b }{ 5 }^{ c }{ 7 }^{ d }$$, find $$a+b+c+d$$.

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