#include <stdio.h>
#include <math.h>

int x,n,i;
void n_pasi()
{
    x=0;
    for(i=1;i<=n;i++)
    {
        x+=floor(log10(i));
    }
    x++;
    printf("\n%d",x);
}

void stirling()
{

    x=0.5*log10(2*3.14*n) + n*log10(n/2.71828)+1; //x=0.5*log10(2*pi*n)+n*log10(n/e)+1;
    printf("\n%d",x);
}

int main()
{
    scanf("%d",&n);
    stirling();
    return 0;
}
//2.253