import sys
f=open("in6_9.txt",'r')
f1=open("out_9_6_9.txt",'w')
import time
start=time.clock()
inputfile1,inputfile2,inputfile3=f.readline().split(",")
x=int(inputfile1)
d=int(inputfile2)
n=int(inputfile3)
b=(n/2)*(2*x+(n-1)*d)
t1=time.clock()-start
total=sys.getsizeof(x)+sys.getsizeof(d)+sys.getsizeof(n)+sys.getsizeof(t1)+sys.getsizeof(b)
f1.write("\nSum of no.="+str(b)+"\ntime="+str(t1)+"\ntotal memory used is="+str(total)+"\nno of muliplication=3"+"\nno of addition=2")
f1.close()
f.close()