#include<stdio.h>#include<time.h>#include<assert.h>#include<math.h>#include<algorithm>#include<string.h>using namespace std;typedef __int64 lld;const int MAX = 64; //262144const int INF = 1000000000;const lld BIT = 1000000000;///定义进制const int MM = 110;struct BigNum{lld dig[MM];int len;void clr(){memset(dig, 0, sizeof(dig));len = 1;}void print(bool flag = false){int i = len - 1;printf("%I64d", dig[i]);for (i--; i >= 0; i--){printf("%09I64d", dig[i]);}if (flag)puts("");}bool zero(){return dig[0] == 0 && len == 1;}bool one(){return dig[0] == 1 && len == 1;}};BigNum add(BigNum a, BigNum b){int i;if (b.len>a.len)a.len = b.len;for (i = 0; i<a.len; i++){a.dig[i] += b.dig[i];if (a.dig[i] >= BIT){a.dig[i + 1]++;a.dig[i] -= BIT;}}if (a.dig[a.len]>0)a.len++;return a;}BigNum multi(BigNum a, BigNum b){int i, j;BigNum c;lld t;c.clr();c.len = a.len + b.len;for (i = 0; i<a.len; i++)for (j = 0; j<b.len; j++){t = (lld)(a.dig[i])*(lld)(b.dig[j]);c.dig[i + j + 1] += (t + (lld)(c.dig[i + j])) / BIT;c.dig[i + j] = (t + (lld)(c.dig[i + j])) % BIT;}if (c.dig[c.len - 1] == 0)c.len--;return c;}BigNum dp[MAX][MAX];BigNum c[MAX][MAX];int main(){int i, j;int n,k;BigNum ONE;ONE.clr();ONE.dig[0] = 1;for (i=0;i<MAX;i++){for (j=0;j<=i;j++){if (j == 0 || j == i)c[i][j] = ONE;else c[i][j] = add(c[i - 1][j] , c[i - 1][j - 1]);}}while (scanf("%d%d", &n,&k) != EOF){for (i = 0; i <= n; i++)for (j = 1; j <= n; j++)dp[i][j].clr();if (k > n)k = n;dp[0][0] = ONE;BigNum ans ;for (i=1;i<=n;i++){for (j=i;j<=n;j++){for (int t=1;t<=k&&t<=j;t++){ans = multi(dp[i - 1][j - t], c[j][t]);dp[i][j] =add(dp[i][j],ans);}}}ans.clr();for (i=1;i<=n;i++){ans =add (dp[i][n],ans);}ans.print(true);if (ans.len > 10)while (1);}return 0;}
