How to go about evaluating the numerical value of three Kronecker delta: $$\delta_{ii}\delta_{jj}\delta_{kk}$$
Tried summing at like this: $$\delta_{ii}\delta_{jj}\delta_{kk}=\delta_{ii}\delta_{ii}\delta_{ii}+\delta_{jj}\delta_{jj}\delta_{jj}+\delta_{kk}\delta_{kk}\delta_{kk}=(3)(3)(3)+(3)(3)(3)+(3)(3)(3)=81$$
But it was marked incorrect.