#include <iostream>
#include <vector>
#define PB push_back
using namespace std;
typedef vector <int> big;
typedef vector <big> BIG;
int n;
big b;
istream& operator>>(istream& stream,big& a){
    string s; stream>>s;
    for(int i=s.size()-1;i>=0;--i)a.PB(s[i]-'0');
    return stream;}
ostream& operator << (ostream& st, big a){
	for (int i = a.size() - 1; i >= 0; --i)
		st << a[i];
	return st;
}
big operator +(big a,big b){
        big c; int i,r=0;
    for(i=0;i<a.size()||i<b.size()||r;++i){
        if(i<a.size())r+=a[i];
        if(i<b.size())r+=b[i];
        c.push_back(r%10);
        r/=10;
    }
    return c;
}
big operator -(big x,big y){
    big z; int i,r=0;
    for(i=0;i<x.size();++i){
        r+=x[i];
        if(i<y.size())r-=y[i];
        if(r<0){
            z.push_back(r+10);r=-1;
        }
        else{
            z.push_back(r);r=0;
        }
    }
    while(z.back()==0 and z.size()>1)
        z.pop_back();
    return z;
}
big operator *(big x,int y){
    big z;
    if(y){
        long long r=0;
        for(auto e:x){
            r+=e*y;z.push_back(r%10);
            r/=10;
        }
        while(r){
            z.push_back(r%10);
            r/=10;
        }
    }
    else
        z.push_back(0);
    return z;
}
big operator *(big x,big y){
    big z,r(1,0);
    for(auto e:x){
        r=r+y*e; z.push_back(r[0]); r.erase(r.begin());
    }
    for(auto e:r)
        z.push_back(e);
    while(z.back()==0 and z.size()>1)
        z.pop_back();
    return z;
}
bool operator >(big a,big b){
    if(a.size()>b.size())
        return true;
    if(a.size()<b.size())
        return false;
    for(int i=a.size()-1;i>=0;--i){
        if(a[i]>b[i])
            return true;
        if(a[i]<b[i])
            return false;
    }
}
bool operator <(big a,big b){
    if(a.size()<b.size())
        return true;
    if(a.size()>b.size())
        return false;
    for(int i=a.size()-1;i>=0;--i){
        if(a[i]<b[i])
            return true;
        if(a[i]>b[i])
            return false;
    }
}


int main()
{
		big  sum(1,0),b;
		BIG Fibo;
		int n, max=0,x;

		cin >> n;
		for (int i=0; i<n;i++)
		{
			cin >> x;
			b.push_back(x);
			if (max < b[i]) max = b[i];
		}

		big one(1,1),zero(1,0);
		Fibo.resize(max+5,zero);
		Fibo[1] = one;
		Fibo[0] = zero;
		for (int i=2;i<max+1; i++)
		{
			Fibo[i]=Fibo[i-1]+Fibo[i-2];
		}
		for (int i=0; i<n; i++)
			sum =sum+Fibo[b[i]];
		cout << sum;
}