#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

template<int N> void mat_prod(LL a[N][N], LL b[N][N], LL c[N][N], LL MOD) { // a = b * c;
	LL d[N][N];
	inc(i, N) {
	inc(j, N) {
		d[i][j] = 0;
	}
	}
	
	inc(i, N) {
	inc(j, N) {
	inc(k, N) {
		(d[i][j] += b[i][k] * c[k][j]) %= MOD;
	}
	}
	}
	
	inc(i, N) {
	inc(j, N) {
		a[i][j] = d[i][j];
	}
	}
	
	return;
}

template<int N> void mat_exp(LL a[N][N], LL b[N][N], LL c, LL MOD) { // a = b ^ c;
	LL t[60][N][N];
	inc(i, N) {
	inc(j, N) {
		t[0][i][j] = b[i][j];
	}
	}
	inc(i, 60 - 1) {
		mat_prod<N>(t[i + 1], t[i], t[i], MOD);
	}
	
	inc(i, N) {
	inc(j, N) {
		a[i][j] = 0;
	}
	}
	inc(i, N) { a[i][i] = 1; }
	inc(i, 60) {
		if((c >> i) % 2 == 1) {
			mat_prod<N>(a, a, t[i], MOD);
		}
	}
	
	return;
}

// ----

LL n, b, d, sw, tw, MOD = 1e9 + 7;

LL m[31], w[31];

int main() {
	cin >> n >> b >> d;
	
	LL a[3][3] = { { d + 1, d, 0 }, { 0, 1, 1 }, { 0, 0, 1 } };
	LL v[3][3] = { { d    , 0, 0 }, { 2, 0, 0 }, { 1, 0, 0 } };
	mat_exp(a, a, b - 1, MOD);
	mat_prod(a, a, v, MOD);
	tw = a[0][0];
	
	int l = 30;
	inc1(i, 30) {
		m[i] = m[i - 1] * (d + 1) + d;
		w[i] = w[i - 1] * (d + 1) + i * d;
		if(m[i] >= n) { l = i; break; }
	}
	m[0] = 1;
	w[0] = 1;
	
	decII(i, 0, l) {
		if(m[i] > n) { continue; }
		
		LL p = m[i] + 1;
		if((n + 1) % p == 0) {
			LL y = (n + 1) / p;
			n -= y * p - 1;
			sw += y * (w[i] + i + 1) - (i + 1);
			assert(n == 0);
			break;
		}
		
		LL y = n / p;
		n -= y * p;
		sw += y * (w[i] + i + 1);
	}
	sw %= MOD;
	
	cout << (tw + MOD - sw) % MOD << endl;
	
	return 0;
}