import sys
sys.setrecursionlimit(10 ** 6)


def dfs(n, s):
    global N, MOD
    rst = 0
    tmp = s
    if n == N - 1:
        rst += s // 2 + 1
    elif (n, s) in dp:
        return dp[(n, s)]
    else:
        while s >= 0:
            rst += dfs(n + 1, s)
            rst %= MOD
            s -= (N - (n - 1))
    dp[(n, tmp)] = rst
    return rst


N, S, K = map(int, input().split())

MOD = 10 ** 9 + 7
init = (N * (N - 1) * K) // 2
if S < init:
    print(0)
else:
    S -= init
    dp = {}
    rst = dfs(1, S)
    print(rst)