b=int(input())
s=input()
d=int(s, b)
if d<b:
  print(d)
  sys.exit()
n=len(s)
n1=1
n2=n
while n1!=n2:
  n0=(n1+n2+1)//2
  x=b
  if n0!=1:
    x=int('1'+('0'*n0), b)*n0-int('1'*n0, b)
  if x<d:
    n1=n0
  else:
    n2=n0-1
d=d-int('1'+('0'*n1), b)*n1+int('1'*n1, b)
p0=int('1'+('0'*n1), b)
i=n1+1
c=(d+i-1)//i
r=b
if d%i!=0:
  r=int('1'+('0'*(i-d%i+1)), b)
x=p0-1+c
x%=r;
print(x//(r//b))