#include <stdio.h>
int main()
{
unsigned long *numitor,*numarator;
numitor=new unsigned long[1000000];
numarator=new unsigned long[1000000];
int k,n;
numarator[1]=1;numitor[1]=1;k=1;
scanf("%d",&n);
int gata=0;
	while(!gata)
	{gata=1;
	for(int i=k;i<=k;i++)
		if(numarator[i]+numitor[i]<=n)
		{k++;
		numitor[k]=numarator[i]+numitor[i];
		numarator[k]=numarator[i];
		k++;
		numarator[k]=numitor[i]+numarator[i];
                 numitor[k]=numitor[i];
                 gata=0;
		}
	}
printf("%ld\n",k);
return 0;
}