radioactive

#include <iostream>
#include <vector>
#include <cstring>
#include <unordered_map>
# define int long long
using namespace std;

const int MOD = 1000000007;
unordered_map<int, int> dp;

int countWays(int N, int C) {
    if (dp.find(N) != dp.end()) return dp[N];

    if (N % 2 == 0) {
        int answer = 0;
        int dpArray[C + 1];
        memset(dpArray, 0, sizeof dpArray);

        for (int i = 0; i <= min(N / 2 + 1, C); i++) {
            if (i == N / 2) {
                dpArray[i] = 1;
            } else {
                dpArray[i] = countWays(N / 2 - i - 1, C);
            }
        }

        int curr = dpArray[0];
        for (int i = C; i >= 0; i--) {
            answer = (answer + dpArray[i] * curr) % MOD;
            curr = (curr + dpArray[C - i + 1]) % MOD;
        }

        return dp[N] = answer;
    }
    else {
        int answer = 0;
        int dpArray[C + 2];
        memset(dpArray, 0, sizeof dpArray);
        dpArray[0] = countWays(N / 2, C);
        for (int i = 1; i <= min(N / 2, C) + 1; i++) {
            if (i == N / 2 + 1) {
                dpArray[i] = 1;
            }
            else {
                dpArray[i] = countWays(N / 2 - i, C);
            }
        }

        int curr = dpArray[0];
        for (int i = C; i >= 0; i--) {
            answer = (answer + dpArray[i + 1] * curr) % MOD;
            curr = (curr + dpArray[C - i + 1]) % MOD;
        }
        return dp[N] = answer;
    }
}

signed main() {
    int N, C;
    cin >> N >> C;

    if (N <= C) {
        int ways = 1;
        for (int i = 0; i < N; ++i) {
            ways = (2 * ways) % MOD;
        }
        cout << ways << endl;
    } else {
        if (N == 0) {
            cout << 1 << endl;
        } else {
            if (N == 1) {
                cout << 2 << endl;
            } else {
                int ways = countWays(N, C);
                cout << ways << endl;
            }
        }
    }

    return 0;
}