#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    ll a[5];
    drep(i,5)cin >> a[i];

    vector<ll> fib;
    fib.push_back(1);
    fib.push_back(1);
    while(true){
        int n = fib.size();
        ll x = fib[n-1] + fib[n-2];
        fib.push_back(x);
        if(x > 1e16)break;
    }

    int n = fib.size();
    int ans = 0;
    rep(i,1){
        rep(j,n){
            if(fib[j] == a[i]){
                int tmp = 0;
                srep(k,i,5){
                    if(a[k] == fib[j + k - i]){
                        tmp++;
                    }else{
                        break;
                    }
                }
                ans = max(ans, tmp);
                break;
            }
        }
    }

    cout << ans << endl;
    return 0;
}