var
i,j,L,n,k,s,t:integer;
b:array[1..10] of 0..9;
begin
readln(L,n);
s:= L; k:=1; t:=L;
while s<n do
begin
k:=k+1; t:=t*L; s:=s+t;
end;
s:=s-t; n:=n-s-1;
for i:=1 to 10 do
b[i]:=0;
j:=11;
while n>0 do
begin
j:=j-1;
b[j]:=n mod L;
n:=n div L;
end;
for i:=10-k+1 to 10 do
write(chr(ord('a')+b[i]));
end.
输入：4 167
输出：bbac