#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <cstring>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <string.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

using namespace std;


#define ld long double
#define F first
#define S second
//
#define int long long
#define ll long long
#define db(x)                cerr<<#x<<": "<<x<<endl
#define db2(x, y)             cerr<<#x<<": "<<x<<" | "<<#y<<": "<<y<<endl
#define db3(x, y, z)          cerr<<#x<<":" <<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<endl
#define db4(a, b, c, d)       cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<endl
#define db5(a, b, c, d, e)    cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<" | "<<#e<< ": "<<e<<endl
#define db6(a, b, c, d, e, f) cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<" | "<<#e<< ": "<<e<<" | "<<#f<<": "<<f<<endl
//
#define mem(x,y) memset(x,y,sizeof(x))
#define bitcount    __builtin_popcount
//
#define pii pair<int, int>
#define all(v) v.begin(),v.end()
//
#define IOS ios_base::sync_with_stdio(false); cin.tie(NULL)
#define vi vector<int>
#define vvi vector< vector<int> >
#define si set<int>
#define pb push_back
#define lp(i,a,b) for(int i=a;i<b;i++)
#define rloop(i,a,b) for(int i=a;i>=b;i--)
#define mk make_pair
const int N=2e5+3;
const int mod=1e9+7;
const int mod1=998244353;
const int inf=1e16+7;
using namespace std;

void solve(){
    int s,w;
    cin>>s>>w;
    if(w>=s){
        cout<<"unsafe";
        else cout<<"safe";
    }
}
 

int32_t main() {
    IOS;
    int t;
  //  cin>>t;
    
    t=1;
    for(int i=1;i<=t;i++){
       // cout<<"Case #"<<i<<": ";
        solve();
        cout<<'\n';
    }
   
}















