n,k = map(int, input().split())
A = list(map(int, input().split()))
A.reverse()

mod = sum(A)

table = [0]*(10**5+1)
table[0] = 1
for i in range(1, 10**5+1):
     table[i] = table[i-1]*k
     table[i] %= mod

ans = 0
for i, a in enumerate(A):
    ans += a*table[i]
    ans %= mod
print(ans)