MOD = 10**9+7
N,S,K = list(map(int,input().split()))

now = [0] * (S+1)
now[0] = 1
for i in range(N):
    next = [0] * (S+1)
    for j in range(S+1):
        if(now[j] == 0):continue
        v = j + K * (N-i) if i > 0 else 0
        while(True):
            if(v > S):break
            next[v] += now[j]
            next[v] %= MOD
            v += N-i
    now,next = next,now
print(now[S])