n,p = map(int,input().split())
mod = 10**9+7
ans = 0
cum = 0
fib = [0,1]
for i in range(n):
    if i >= 2:
        fib.append((fib[-1]*p+fib[-2])%mod)
    cum += fib[i]
    cum %= mod

    ans += cum*fib[i]
    ans %= mod
print(ans)