#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

//template
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(a);i>(b);i--)
#define ALL(v) (v).begin(),(v).end()
typedef long long int ll; const int inf = 0x3fffffff; const ll INF = 0x3fffffffffffffff;
template<class T> inline bool chmax(T& a,T b){ if(a<b){a=b;return 1;}return 0; }
template<class T> inline bool chmin(T& a,T b){ if(a>b){a=b;return 1;}return 0; }
//template end

vector<ll> fib={1,1};

int main(){
    ll a[5]; rep(i,0,5)scanf("%lld",&a[i]);
    reverse(a,a+5);
    ll f=1,s=1;
    while(f<1e15){
        fib.push_back(f+s);
        f=s; s=fib.back();
    }
    int ans=0;
    rep(i,0,fib.size()){
        if(fib[i]>a[0])break;
        if(fib[i]==a[0]){
            rep(j,0,5){
                if(i+j>=fib.size())break;
                if(fib[i+j]==a[j])chmax(ans,j+1);
                else break;
            }
        }
    }
    printf("%d\n",ans);
    return 0;
}