#include <iostream>
#include <algorithm>
using namespace std;
using i64 = long long;

class range {private: struct I{int x;int operator*(){return x;}bool operator!=(I& lhs){return x<lhs.x;}void operator++(){++x;}};I i,n;
public:range(int n):i({0}),n({n}){}range(int i,int n):i({i}),n({n}){}I& begin(){return i;}I& end(){return n;}};

const int mod = int(1e9) + 7;

int f(int n, int k) {
  vector<vector<i64>> dp(k+1, vector<i64>(n+1));
  dp[0][0] = 1;
  for(int i : range(1, k+1)) {
    for(int j : range(n+1)) {
      dp[i][j] = dp[i-1][j] + (j >= i ? dp[i][j-i] : 0) % mod;
    }
  }
  return dp[k][n] % mod;
}

int main(void) {
  int n, s, k; scanf("%d%d%d", &n, &s, &k);
  int x = s - n * (n-1) / 2 * k;
  int res = x>=0 ? f(x, n) : 0;
  printf("%d\n", res);
  return 0;
}