#include<bits/stdc++.h>
#include<vector>
#include<iostream>
#include<sstream>
#include<fstream>
#include<list>
#include<deque>
#include<queue>
#include<stack>
#include<map>
#include<set>
#include<bitset>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cctype>
#include<cmath>
#include<ctime>
#include<iomanip>
#include<string>
using namespace std;
/*freopen{"input.txt","r",stdin};
freopen{"output.txt","w",stdout};*/
#define mp make_pair
#define pb push_back
const int INF=1000*1000*1000;
const int maxn=2e5; 
typedef long long ll;
typedef long double ld;
typedef pair<int,int>PII;
//priority_queue <int,vector<int>,greater<int> > q1;  //从小到大 
//priority_queue <int,vector<int>,less<int> >q2;  //从大到小 

int main(){
	//ios_base::sync_with_stdio(0);
    //cin.tie(0);
    //cout.tie(0);
    int a,b;
	cin>>a>>b;
	if(a<b)
	cout<<"unsafe";
	else
	cout<<"safe";
    
    
    
    return 0;
}

