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#include <iostream>
#include <unordered_map>
#include <utility>

int n, m;
int p = 1000000007;
long long m_pow[3005];
long long dp[3005];

void input() {
    std::cin >> n >> m;
}

void prepare_m_pow() {
    m_pow[0] = 1;
    for (int i = 1; i < n; i++) {
        m_pow[i] = (m_pow[i - 1] * m) % p;
    }
}

long long pow_mod(int a, int b) {
    if (b == 0) {
        return 1;
    }
    if (b == 1) {
        return a % p;
    }
    if (b % 2 == 1) {
        return (pow_mod(a, b - 1) * a) % p;
    }
    return pow_mod((((long long)a) * a) % p, b / 2); 
}

long long solve() {
    long long m_inv = pow_mod(m, p - 2);
    dp[1] = 0;
    dp[2] = m;
    for (int k = 3; k <= n; k++) {
        long long result = m_pow[k - 1];
        for (int i = 2; i <= k - 2; i++) {
            long long r = (dp[i] * dp[k - i]) % p;
            r = (r * (m - 1)) % p;
            r = (r * m_inv) % p;
            result = (result + r) % p;
        }
        dp[k] = result;
    }
    return dp[n];
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(NULL);
    input();
    prepare_m_pow();

    std::cout << solve() << "\n";    
    
    return 0;
}