Functions count the of functions f:[ml→[m In] [m] (f(1),f(2),.,f(n)∈[m]m one-one correspondence [nl→[ml台[mmFunctions [n] [m] f : [n] ￾ [m] count the # of functions ￾ [m] n one-one correspondence [n] ￾ [m] ⇥ [m] n (f(1), f(2),...,f(n))