Suppose that the graph of a certain function, y=f(x), has the property that if it is shifted 20 units to the right, then the resulting graph is identical to the original graph of y=f(x). What is the smallest positive a such that if the graph of \(y=f\left(\frac x5\right)\) is shifted a units to the right, then we know that the resulting graph is identical to the original graph of \(y=f\left(\frac x5\right)\)?