#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const int N = 1e6 + 4;
long long fac[N], infac[N];
long long me(long long a, long long b) {
  long long res = 1;
  while (b) {
    if (b & 1) res = (res * a) % mod;
    b >>= 1;
    a = (a * a) % mod;
  }
  return res;
}
long long mi(long long n) { return me(n, mod - 2); }
void factorial() {
  fac[0] = 1;
  for (long long i = 1; i < N; i++) fac[i] = (i * fac[i - 1]) % mod;
  infac[N - 1] = mi(fac[N - 1]);
  for (long long i = N - 1; i > 0; i--) infac[i - 1] = (i * infac[i]) % mod;
}
long long ncr(long long n, long long r) {
  if (n < r) return 0;
  long long res = fac[n];
  res = (res * infac[r]) % mod;
  res = (res * infac[n - r]) % mod;
  return res;
}
int main() {
  factorial();
  long long n, m;
  scanf("%lld", &n);
  scanf("%lld", &m);
  long long ans = me(m, n);
  for (long long s = 1; s <= n; s++) {
    long long val = me(m, s), temp = me(m - 1, n - s);
    val = (val * temp) % mod;
    val = (val * ncr(n, s - 1));
    ans = (ans + val) % mod;
  }
  printf("%lld", ans);
  return 0;
}
