Time Complexity: Towers of Hanoi

Can any explain what the time complexity of the algorithm is? Thanks.

Algorithm:

H3(n, S, A1, A2, A3, D) {

If (n == 1)

S to A1 to A2 to A3

A3 to D (if remaining disk)

Else{

H3(n-1, S, A1, A2, A3, D)

S to Aux1 to Aux2

H2(n-1, S, A3, A1, A3, D)

A2 to A3

A3 to D (if disk n is able to move)

H3(n-1, S, A1, A2, A3, D)

}

}

H2(n, S, A1, A2, A3, D) {

If (n ==1)

A1 to A2

Else{

H3(n-1, S, A1, A2, A3, D)

A1 to A2

H3(n-1, S, A3, A1, A2, D)

}

}