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

int main(){
	int a[1000],n,i,x = 0,d = 0;
	cin>>n;
	for(i = 0;i < n;i++){
		cin>>a[i];
		if(a[i] >= 90){
			x++;
		}else if(a[i] < 60){
			d++;
		}
	}
	
	if(d == 0){
		if(x == 5){
			cout<<1<<endl;
		}else if(x == 3|| x == 4){
			cout<<2<<endl;
		}else if(x == 2){
			cout<<3<<endl;
		}
	}else{
		cout<<"no"<<endl;
	}
}


/**************************************************************
	Problem: 1429
	User: admin
	Language: C++
	Result: Accepted
	Time:13 ms
	Memory:2072 kb
****************************************************************/