#include<cstdio>
#include<iostream>
#include<cmath>
using namespace std;
int main()
{
int a,n;
double sum;
cin>>n;
for(int i=1;i<=n;i++)
{
sum+=log(i)/log(10);
}
a=int(sum)+1;
cout<<a;
return 0;
}
#include<cstdio>
#include<iostream>
#include<cmath>
using namespace std;
int main()
{
int a,n;
double sum;
cin>>n;
for(int i=1;i<=n;i++)
{
sum+=log(i)/log(10);
}
a=int(sum)+1;
cout<<a;
return 0;
}