PROGRAM NOI_002;
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