#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

const int MOD = 1000000007;

// 行列の積
template <class T>
vector<vector<T> > matrixProduct(const vector<vector<T> >& x, const vector<vector<T> >& y)
{
    int a = x.size();
    int b = x[0].size();
    int c = y[0].size();
    vector<vector<T> > z(a, vector<T>(c, 0));
    for(int i=0; i<a; ++i){
        for(int j=0; j<c; ++j){
            for(int k=0; k<b; ++k){
                z[i][j] += x[i][k] * y[k][j];
                z[i][j] %= MOD;
            }
        }
    }
    return z;
}

// 行列の累乗
template <class T>
vector<vector<T> > matrixPower(const vector<vector<T> >& x, int k)
{
    int n = x.size();
    vector<vector<T> > y(n, vector<T>(n, 0));
    for(int i=0; i<n; ++i)
        y[i][i] = 1; // 積の単位元

    vector<vector<T> > z = x;
    while(k > 0){
        if(k & 1)
            y = matrixProduct(y, z);
        z = matrixProduct(z, z);
        k >>= 1;
    }
    return y;
}

long long solve(long long b, long long d, long long cnt, long long weight, long long& n)
{
    if(cnt > n)
        return 0;
    long long ans = solve(b + 1, d, cnt * (d + 1) + d, weight * (d + 1) + b * d, n);

    long long x = n / (cnt + 1);
    n -= (cnt + 1) * x;
    ans += (weight + b) * x;
    ans %= MOD;
    return ans;
}

int main()
{
    int n, b, d;
    cin >> n >> b >> d;

    vector<vector<long long> > mat =
    {
        {d+1, d, 0},
        {0, 1, 1},
        {0, 0, 1}
    };
    mat = matrixPower(mat, b);
    long long ans = mat[0][1] + mat[0][2];
    ans %= MOD;

    long long tmp = n;
    ans += MOD - solve(1, d, 0, 0, tmp);
    ans %= MOD;
    cout << ans << endl;

    return 0;
}