#include <fstream>
#define dimmax 1000

using namespace std;

ifstream in("pascal.in");
ofstream out("pascal.out");

unsigned long nr,i,j,r,pascal[dimmax][dimmax];
unsigned d;

int main() {
    in >> r >> d;
    pascal[0][0] = pascal[1][0] = pascal[1][1] = 1;
    for(i=2;i<=r;i++) {
        pascal[i][0] = pascal[i][i] = 1;
        for(j=1;j<i;j++) {
            pascal[i][j] = pascal[i-1][j] + pascal[i-1][j-1];
            if(!(pascal[i][j])) nr++;
        }
    }
    out << nr;
    return 0;
}