#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;
}