const
    kk=3;
    a:array[1..kk] of longint=(1,2,6);

var
    n,i,j:longint;
    f:array[-10..110,0..kk] of longint;

begin
reset(input,'input.txt');
rewrite(output,'output.txt');
fillchar(f,sizeof(f),0);
read(n);
for i:=0 to kk do
    f[0][i]:=1;
for i:=1 to n do
    for j:=1 to kk do
            f[i][j]:=f[i-a[j]][j]+f[i][j-1];
write(f[n][kk]);
end.