#include<stdio.h>
 
int factorial(int n){
    if(n==1 || n==0) return 1;
    else return(n*factorial(n-1));
}
 
int comb(int n,int r){
    int C = factorial(n)/(factorial(r)*factorial(n-r));
    return(C);
}
 
int result(int e,int m){
    int i, p, sum=1;
    p = e/m;
    for(i=2; i<=p; i++){
    int k = comb((e-1-m*i-i) , (i-1));
    sum += k/i;
    }
    return sum;
}
 
int main(){
    int e,m;
    scanf("%d %d\n",&e,&m);
    int r = result(e,m);
    printf("%d\n",r);
    return 0;
}

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