flag="*********"
def RabinKarpRollingHash( str, a, n ):
        result = 0
        l = len(str)
        for i in range(0, l):
                result += ord(str[i]) * a ** (l - i - 1) % n
        print "result = ", result


RabinKarpRollingHash(flag, 256, 10**30)
output is 
1317748575983887541099 
What is the flag?