s=input().split(' ')
a=eval(s[0])
b=eval(s[1])
ss=s[2]
sum=0
p=1
ans=""
d={'A':10,'B':11,'C':12,'D':13,'E':14,'F':15,'G':16,'H':17,'I':18,'J':19,'K':20,'L':21,'M':22,'N':23,'O':24,'P':25,'Q':26,'R':27,'S':28,'T':29,'U':30,'V':31,'W':32,'X':33,'Y':34,'Z':35,'a':36,'b':37,'c':38,'d':39,'e':40,'f':41,'g':42,'h':43,'i':44,'j':45,'k':46,'l':47,'m':48,'n':49,'o':50,'p':51,'q':52,'r':53,'s':54,'t':55,'u':56,'v':57,'w':58,'x':59,'y':60,'z':61}
for i in range(len(ss)-1,-1,-1):
    if(ss[i]<='9' and ss[i]>='0'):
        sum+=eval(ss[i])*p
        p=p*a
    else:
        sum+=d[ss[i]]*p
        p=p*a
if(sum==0):
    ans+='0'
while(sum>0):
    t=sum%b
    sum=sum//b
    if(t<10):
        ans+=str(t)
    elif(t<36):
        ans+=chr(55+t)
    else:
        ans+=chr(61+t)
print(ans[::-1])