#include <stdio.h>

int f ( int n )
{
    int i, r;
    
    r = 1;
    if (n > 0) {
        for (i=0; i<=n-1; ++i) r += f(i);
    }
    return r;
}

int main ( )
{
    int n;
    
    printf("n = "); scanf("%d", &n);
    printf("f(%d) = %d\n", n, f(n));
    return 0;
}