#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define repr(i, a, b) for (int i = (int)(a); i < (int)(b); i++) #define rep(i, n) repr(i, 0, n) #define INF 2e9 #define MOD 1000000007 //#define MOD 998244353 #define LINF (long long)4e18 #define jck 3.141592 #define PI acos(-1.0); const double EPS = 1e-10; using ll = long long; using Pi = pair; using Pl = pair; int main(){ int N; cin >> N; ll p; cin >> p; vector a(N); a[0] = 0,a[1] = 1; rep(i,N-2){ a[i+2] = (p*a[i+1]%MOD+a[i])%MOD; } vector sum(N+1); rep(i,N) sum[i+1] = (sum[i]+a[i])%MOD; ll ans = 0; rep(i,N){ ans += a[i]*((sum[N]-sum[i]+MOD)%MOD)%MOD; ans %= MOD; } cout << ans << endl; }