using System; using System.Linq; static class P { static void Main() { var np = Console.ReadLine().Split().Select(int.Parse).ToArray(); var n = np[0]; var p = np[1]; Assert(1 <= n && n <= 2 * 1000000); Assert(1 <= p && p <= 1000000000); var fib = new ModInt[n]; if (n != 1) fib[1] = 1; for (int i = 2; i < n; i++) fib[i] = fib[i - 1] * p + fib[i - 2]; ModInt side = 0; ModInt diagnal = 0; for (int i = 0; i < n; i++) { side += fib[i]; diagnal += fib[i] * fib[i]; } Console.WriteLine((side * side + diagnal) / 2); } static void Assert(bool b) { if (!b) throw new Exception(); } } struct ModInt { public const int Mod = 1000000007; const long POSITIVIZER = ((long)Mod) << 31; long Data; public ModInt(long data) { if ((Data = data % Mod) < 0) Data += Mod; } public static implicit operator long(ModInt modInt) => modInt.Data; public static implicit operator ModInt(long val) => new ModInt(val); public static ModInt operator +(ModInt a, int b) => new ModInt() { Data = (a.Data + b + POSITIVIZER) % Mod }; public static ModInt operator +(ModInt a, long b) => new ModInt(a.Data + b); public static ModInt operator +(ModInt a, ModInt b) { long res = a.Data + b.Data; return new ModInt() { Data = res >= Mod ? res - Mod : res }; } public static ModInt operator -(ModInt a, int b) => new ModInt() { Data = (a.Data - b + POSITIVIZER) % Mod }; public static ModInt operator -(ModInt a, long b) => new ModInt(a.Data - b); public static ModInt operator -(ModInt a, ModInt b) { long res = a.Data - b.Data; return new ModInt() { Data = res < 0 ? res + Mod : res }; } public static ModInt operator *(ModInt a, int b) => new ModInt(a.Data * b); public static ModInt operator *(ModInt a, long b) => a * new ModInt(b); public static ModInt operator *(ModInt a, ModInt b) => new ModInt() { Data = a.Data * b.Data % Mod }; public static ModInt operator /(ModInt a, ModInt b) => new ModInt() { Data = a.Data * GetInverse(b) % Mod }; public static bool operator ==(ModInt a, ModInt b) => a.Data == b.Data; public static bool operator !=(ModInt a, ModInt b) => a.Data != b.Data; public override string ToString() => Data.ToString(); public override bool Equals(object obj) => (ModInt)obj == this; public override int GetHashCode() => (int)Data; static long GetInverse(long a) { long div, p = Mod, x1 = 1, y1 = 0, x2 = 0, y2 = 1; while (true) { if (p == 1) return x2 + Mod; div = a / p; x1 -= x2 * div; y1 -= y2 * div; a %= p; if (a == 1) return x1 + Mod; div = p / a; x2 -= x1 * div; y2 -= y1 * div; p %= a; } } }