line = input()
inputt=line.split(' ')
x=inputt[0]
y=inputt[1]
x=int(x)
y=int(y)
s=inputt[2]
a=0


def itoc (a):
    if a>=0 and a<=9:
        return chr((a) +ord('0'))
    if a >= 10 and a <= 35:
        return chr(ord('A') + a -10)
    if a >= 36 and a <= 61:
        return chr(ord('a') + a -36)

def ctoi (a):
    if a>='0' and a<='9':
        return ord(a)-ord('0')
    if a>='A' and a<='Z':
        return ord(a) - ord('A') + 10
    if a>='a' and a<='z':
        return ord(a) - ord('a') + 36
if s=='0':
    print(0)
    exit(0)
for i in range(0,len(s)):
    a*=x
    a+=ctoi((s[i]))
l=""
while a>0:
    b=a%y
    l=(itoc(b))+l
    a-=b
    a=a//y

print(l)