import std.stdio, std.array, std.string, std.conv, std.algorithm; import std.typecons, std.range, std.random, std.math, std.container; import std.numeric, std.bigint, core.bitop, core.stdc.string; immutable long MOD = 10^^9 + 7; long powmod(long a, long x, long m) { long ret = 1; while (x) { if (x % 2) ret = ret * a % MOD; a = a * a % MOD; x /= 2; } return ret; } void main() { immutable long MAX = 2*10^^6+1; immutable long MOD = 10^^9+7; auto modinv = new long[](MAX); modinv[0] = modinv[1] = 1; foreach(i; 2..MAX) { modinv[i] = modinv[MOD % i] * (MOD - MOD / i) % MOD; } auto f_mod = new long[](MAX); auto f_modinv = new long[](MAX); f_mod[0] = f_mod[1] = 1; f_modinv[0] = f_modinv[1] = 1; foreach(i; 2..MAX) { f_mod[i] = (i * f_mod[i-1]) % MOD; f_modinv[i] = (modinv[i] * f_modinv[i-1]) % MOD; } long H(long a, long b) { if (a == 0 && b == 0) return 1; if (a == 0) return 0; if (b == 0) return 1; return f_mod[a+b-1] * f_modinv[a-1] % MOD * f_modinv[b] % MOD; } auto s = readln.split.map!(to!long); auto N = s[0]; auto K = s[1]; auto D = s[2]; auto P = new long[](N+1); P[0] = 1; foreach (i; 0..N) P[i+1] = P[i] * D % MOD; auto X = N / (K-1); auto Y = N % (K-1); if (Y == 0) X -= 1, Y = K-1; if (D == 1) { writeln(Y); return; } long ans = 0; foreach (i; 0..X+1) { // D^i auto nokori = X - i; // nokori 個を (Y-1) 個 に分配する場合の数 auto tmp = Y * powmod(D, i, MOD) % MOD * H(Y-1, X-i) % MOD; ans += Y * powmod(D, i, MOD) % MOD * H(Y-1, X-i) % MOD; ans %= MOD; //writeln(i, " ", tmp); } ans.writeln; }