#include <iostream>

using namespace std;

const int MOD = 1000000007;

int n, b, d, inv, ans;

int QMI(int a, int k) {
    int ret = 1 % MOD;
    while (k) {
        if (k & 1) {
            ret = 1LL * ret * a % MOD;
        }
        a = 1LL * a * a % MOD;
        k >>= 1;
    }
    return ret;
}

int main() {
    scanf("%d%d%d", &n, &b, &d);

    ans = QMI(d + 1, b + 1) - 1;
    (ans += MOD) %= MOD;
    inv = QMI(d, MOD - 2);
    ans = 1LL * ans * inv % MOD;

    while (n > 0) {
        ans = (ans - n % MOD + MOD) % MOD;
        n /= (d + 1);
    }
    ans = (ans - (b + 1) + MOD) % MOD;
    printf("%d\n", ans);

    return 0;
}