43. Given 3 numbers A,B,C find the sum of Arithmetic Series with a=A, d=B and n=C

Given 3 numbers A,B,C find the sum of Arithmetic Series with a=A, d=B and n=C
Sample Testcase :
INPUT
1 1 2
OUTPUT
3


#Formula:((n / 2) * (2 * a + (n - 1) * d))
#Given -- >a=A, d=B and n=C
A,B,C=(int(no) for no in input().split())
result=((C/2)*(2*A+(C-1)*B))
print(round(result))