#include<iostream>
#include<cstdio>
#include<cstdlib>
using namespace std;
long long n;
long long q[505][505]={0};
int main()
{
freopen ("runa.in","r",stdin);
freopen ("runa.out","w",stdout);
cin>>n;
for (int i=0;i<=n;i++)
q[0][i]=1;
for (int i=1;i<=n;i++)
{
for (int j=1;j<=n;j++)
{
q[i][j]=q[i][j-1];
if (i-j>=0)
q[i][j]+=q[i-j][j-1];
}
}
cout<<q[n][n]-1;
return 0;
}