import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
n,s,k = na()
dp = [0] * (s+1)
dp[0] = 1
mod = 10**9+7
for i in range(n):
    ndp = [0]*(s+1)
    ndp, dp = dp, ndp
    nk = k if i else 0
    for j in range(s+1):
        if j - (n - i) >= 0:
            dp[j] += dp[j-(n-i)]
        if j - nk*(n-i) >= 0:
            dp[j] += ndp[j-nk*(n-i)]
            dp[j] %= mod
    #print(dp)
print(dp[-1])