#!/usr/bin/python2
# -*- coding: utf-8 -*-
# †
def rep(B, i):
    return (B**i - 1) / (B-1)

def g(B, i):
    if i == 1:
        return 1
    if i == 2:
        return B
    return (i-2) * B**(i-1) + rep(B, i-1) * (B-2) + 2


def f(B, D):
    lo, hi = 0, 10**6
    while hi - lo > 1:
        md = (lo + hi) / 2
        if g(B, md) <= D:
            lo = md
        else:
            hi = md
    pos = g(B, lo)
    dif = D - pos
    z, r = divmod(dif, lo)
    w = z + B**(lo-1)
    return (w / B**(lo-1-r)) % B

B = int(raw_input())
D = int(raw_input(), base=B)
res = f(B, D)
print res