if days $==0$:

return pennies# Returns number of pennies if pennies are doubled num$\_$days times

def double$\_$pennies$($num$\_$pennies, num$\_$days$)$:

total$\_$pennies $=0$

else:

total$\_$pennies $=$ double$\_$pennies$(($num$\_$pennies $*2),($num$\_$days $-1))$

return total$\_$pennies

# Program computes pennies if you have $1$ penny today,

# $2$ pennies after one day, $4$ after two days, and so on

starting$\_$pennies $=$ int$($input$())$

user$\_$days $=$ int$($input$())$

print$(\text{'}$Number of pennies after', user$\_$days, 'days: $\text{'},$ end$="")$

print$($double$\_$pennies$($starting$\_$pennies, user$\_$days$))$