If it takes $$0\mathrm{.}71$ U$.$S$.$ dollars to purchase one Swiss franc, how many Swiss francs can one U$.$S$.$ dollar buy?

$0\mathrm{.}2\mathrm{.}31$

b$.0\mathrm{.}50$

c$.0\mathrm{.}71$

d$.1\mathrm{.}41$

e$.1\mathrm{.}00$