import bisect
import copy
import decimal
import fractions
import functools
import heapq
import itertools
import math
import random
import sys
from collections import Counter,deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines
N,S,K=map(int,readline().split())
mod=10**9+7
dp=[0]*(S+1)
dp[0]=1
for n in range(1,N+1):
    prev=dp
    dp=[0]*(S+1)
    for s in range(K*(n-1),S+1):
        if s>=n:
            dp[s]=dp[s-n]
        dp[s]+=prev[s-K*(n-1)]
        dp[s]%=mod
ans=dp[S]
print(ans)