ENV[Z='RUBY_THREAD_VM_STACK_SIZE']||exec({Z=>?5*8},'ruby',$0)
P=[1]
g=->k{
	P[k]||=B*g[k-1]
}
M=[0]
f=->k{
	M[k]||=k*g[k-1]*(B-1)+f[k-1]
}

B = gets.to_i
D = (S=gets).to_i(B)
n = (1..S.size).bsearch{|k|
	D <= f[k]
}
DD = D+(B**n-1)/(B-1)-1
puts (DD/n).to_s(B)[DD%n]