def convert(input, source, target):
    sbase = len(source)
    tbase = len(target)
    
    value = 0
    for i,c in enumerate(input):
        p = len(input)-i-1
        b = source.index(c)
        value += b * sbase ** p

    print(value)

    if value == 0:
        return target[0]
    
    output = ""
    while value > 0:
        b = target[value % tbase]
        output = b + output
        value = value // tbase
    print("%s -> %s" % (input,output))
    return output

dec = "0123456789"
hex = dec + "ABCDEF"
bin = "01"

convert("15",dec,bin)