n, s, k = map(int, input().split())
MOD = 10 ** 9 + 7


dp = [[0] * (s + 1) for i in range(n)]
for ki in range(s + 1):
    if ki * n > s:
        break
    dp[0][ki * n] = 1

for i in range(n - 1):
    for si in range(s + 1):
        if si - k * (n - (i + 1)) >= 0:
            dp[i + 1][si] += dp[i][si - k * (n - (i + 1))]
        if si - (n - (i + 1)) >= 0:
            dp[i + 1][si] += dp[i + 1][si - (n - (i + 1))] 
        dp[i + 1][si] %= MOD

print(dp[-1][-1] % MOD)