#include<iostream>
#include<array>

#define REP(i,N) for(int i=0,__i=N;i<__i;++i)

long long __next;
#define fibo_advance(a,b,c) \
	__next=b+c;\
	a=b;\
	b=c;\
	c=__next

std::array<long long,5> a;

bool input(){
	REP(i,5)
		std::cin>>a[5-1-i];
	return true;
}

int solve(){
	using namespace std;
	long long n1=0,n2=0,n3=1;
	long long count=0,tmp;
	while(a[count]>=n3){
		if(a[count]==n3)
			count++;
		fibo_advance(n1,n2,n3);
		//cout<<"a[i]"<<a[count]<<endl;
		//cout<<n1<<","<<n2<<","<<n3<<endl;
	}
	return count;

}

int main(){
	input();
	int res=solve();
	std::cout<<res<<std::endl;
}