#!/usr/bin/python
mod = int(1e9) + 7

def f(n, k):
    dp = [[0 for _ in xrange(n+1)] for _ in xrange(k+1)]
    dp[0][0] = 1
    for i in xrange(1, k+1):
        for j in xrange(n+1):
            if j - i >= 0:
                dp[i][j] = dp[i-1][j] + dp[i][j-i]
            else:
                dp[i][j] = dp[i-1][j]
    return dp[k][n]

n, s, k = map(int, raw_input().split())
x = s - n * (n-1) / 2 * k
print f(x, n) % mod if x >= 0 else 0