class Modint: MOD = 1000000007 def __init__(self, value: int) -> None: self.num = int(value) % self.MOD def __str__(self) -> str: return str(self.num) __repr__ = __str__ def __add__(self, __x): if isinstance(__x, Modint): return Modint((self.num + __x.num)) return Modint(self.num + __x) def __sub__(self, __x): if isinstance(__x, Modint): return Modint(self.num - __x.num) return Modint(self.num - __x) def __mul__(self, __x): if isinstance(__x, Modint): return Modint(self.num * __x.num) return Modint(self.num * __x) __radd__ = __add__ __rmul__ = __mul__ def __rsub__(self, __x): if isinstance(__x, Modint): return Modint(__x.num - self.num) return Modint(__x - self.num) def __pow__(self, __x): if isinstance(__x, Modint): return Modint(pow(self.num, __x.num, self.MOD)) return Modint(pow(self.num, __x, self.MOD)) def __rpow__(self, __x): if isinstance(__x, Modint): return Modint(pow(__x.num, self.num, self.MOD)) return Modint(pow(__x, self.num, self.MOD)) def __truediv__(self, __x): if isinstance(__x, Modint): return Modint(self.num * pow(__x.num, self.MOD - 2, self.MOD)) return Modint(self.num * pow(__x, self.MOD - 2, self.MOD)) def __rtruediv__(self, __x): if isinstance(__x, Modint): return Modint(__x.num * pow(self.num, self.MOD - 2, self.MOD)) return Modint(__x * pow(self.num, self.MOD - 2, self.MOD)) def main(): N, d, K = map(int, input().split()) dp_table = [[Modint(0) for _ in range(K+1)] for _ in range(N+1)] dp_table[0][0] = Modint(1) for number in range(1, N+1): stair_accum = [Modint(0) for _ in range(K+1)] for stair in range(1, K+1): stair_accum[stair] = stair_accum[stair-1] + \ dp_table[number-1][stair-1] dp_table[number][stair] = stair_accum[stair] - \ stair_accum[max(0, stair-d)] print(dp_table[N][K]) if __name__ == "__main__": main()