import sys
import math
from collections import deque
import copy
import bisect

MOD = 10 ** 9 + 7
N, S, K = map(int, input().split())
dp = [[0 for _ in range(S + 10)] for _ in range(N + 10)]
dp[0][0] = 1
if N*N*K/2 > S:
    print(0)
    sys.exit()
for i in range(0, N + 1):
    for l in range(1, S + 1):
        if (l - (N - i)) >= 0:
            dp[i][l] = (dp[i - 1][l - (N - i)] + dp[i][l - (N - i)]) % MOD
print(dp[N - 1][S])