import std.algorithm, std.conv, std.range, std.stdio, std.string;

const mod = 10 ^^ 9 + 7;
alias FactorRing!mod mint;

void main()
{
  auto rd = readln.split.to!(long[]), n = rd[0], m = mint(rd[1]);

  auto r = repeatedSquare(m, n), c = mint(1);
  foreach (i; 1..m) {
    c *= (m - i + 1) * mint(i).inv;
    r += c * repeatedSquare(m - i, n) * (-1) ^^ i;
  }

  writeln(r);
}

T repeatedSquare(T, alias pred = "a * b", U)(T a, U n)
{
  return repeatedSquare(a, n, T(1));
}

T repeatedSquare(T, alias pred = "a * b", U)(T a, U n, T init)
{
  import std.functional;
  alias predFun = binaryFun!pred;

  if (n == 0) return init;

  auto r = init;
  while (n > 0) {
    if ((n & 1) == 1)
      r = predFun(r, a);
    a = predFun(a, a);
    n >>= 1;
  }

  return r;
}

struct FactorRing(int m, bool pos = false)
{
  long v;

  @property int toInt() { return v.to!int; }
  alias toInt this;

  this(T)(T _v) { v = mod(_v); }

  ref FactorRing!(m, pos) opAssign(int _v)
  {
    v = mod(_v);
    return this;
  }

  pure auto mod(long _v) const
  {
    static if (pos) return _v % m;
    else return (_v % m + m) % m;
  }

  pure auto opBinary(string op: "+")(long rhs) const { return FactorRing!(m, pos)(v + rhs); }
  pure auto opBinary(string op: "-")(long rhs) const { return FactorRing!(m, pos)(v - rhs); }
  pure auto opBinary(string op: "*")(long rhs) const { return FactorRing!(m, pos)(v * rhs); }

  pure auto opBinary(string op)(FactorRing!(m, pos) rhs) const
    if (op == "+" || op == "-" || op == "*") { return opBinary!op(rhs.v); }

  auto opOpAssign(string op: "+")(long rhs) { v = mod(v + rhs); }
  auto opOpAssign(string op: "-")(long rhs) { v = mod(v - rhs); }
  auto opOpAssign(string op: "*")(long rhs) { v = mod(v * rhs); }

  auto opOpAssign(string op)(FactorRing!(m, pos) rhs)
    if (op == "+" || op == "-" || op == "*") { return opOpAssign!op(rhs.v); }

  pure auto inv() const
  {
    int x = v.to!int, a, b;
    exEuclid(x, m, a, b);
    return FactorRing!(m, pos)(a);
  }
}

pure T exEuclid(T)(T a, T b, ref T x, ref T y)
{
  auto g = a;
  x = 1;
  y = 0;
  if (b != 0) {
    g = exEuclid(b, a % b, y, x);
    y -= a / b * x;
  }
  return g;
}