#include <bits/stdc++.h>

constexpr std::int64_t MOD = 1e9 + 7;

int main() {
    std::int64_t N, S, K;

    std::cin >> N >> S >> K;

    std::vector<std::vector<std::map<std::int64_t, std::int64_t>>> dp(N + 1, std::vector<std::map<std::int64_t, std::int64_t>>(S + 1));

    // endo
    for (auto i : std::views::iota(0, S + 1))
        dp[0][i][i] = 1;

    std::int64_t result = 0;
    
    for (auto i : std::views::iota(1, N)) {
        for (auto j : std::views::iota(K, S + 1)) {
            if (j > 0)
                for (auto [index, value] : dp[i][j - 1]) {
                   if (index <= S) 
                        dp[i][j][index + 1] = (dp[i][j][index + 1] + value) % MOD;
                }
            
            for (auto [index, value] : dp[i - 1][j - K]) {
                if (index + j <= S) 
                    dp[i][j][index + j] = (dp[i][j][index + j] + value) % MOD;
            }
        }

        // release
        dp[i - 1].clear();
    }

    for (auto j : std::views::iota(K, S + 1)) {
        result = (result + dp[N - 1][j][S]) % MOD;
    }
    
    std::cout << result << std::endl;
    
    return 0;
}