#include <bits/stdc++.h>
/*
                 ,,ggddY888Ybbgg,,
          ,agd8""'   .d8888888888bga,
       ,gdP""'     .d88888888888888888g,
     ,dP"        ,d888888888888888888888b,
   ,dP"         ,8888888888888888888888888b,
  ,8"          ,8888888P"""88888888888888888,
 ,8'           I888888I    )88888888888888888,
,8'            `8888888booo8888888888888888888,
d'              `88888888888888888888888888888b
8                `"8888888888888888888888888888
8                  `"88888888888888888888888888
8                      `"8888888888888888888888
Y,                        `8888888888888888888P
`8,                         `88888888888888888'
 `8,              .oo.       `888888888888888'
  `8a             8888        88888888888888'
   `Yba           `""'       ,888888888888P'
     "Yba                   ,88888888888'
       `"Yba,             ,8888888888P"'
          `"Y8baa,      ,d88888888P"'
               ``""YYba8888P888"'
*/
using namespace std;
#define int long long
#define KOD ios_base::sync_with_stdio(0) , cin.tie(0) , cout.tie(0) ;
#define sz size()
#define S second
#define X(a,b) a = ((b) > (a)) ? (b) : (a);
#define N(a,b) a = ((b) > (a)) ? (a) : (b);
#define F first
#define SORT(x) sort(x.begin(),x.end())
#define Rev(a) reverse(a.begin() , a.end());
#define pb push_back
#define pre(x) cout.precision(0);
#define bit(x) __builtin_popcount(x)
#define is(a) insert(a);
typedef vector<int> vi;
typedef pair<int,int> pi;
typedef unordered_map<int,int> wi;
typedef unordered_set<int> si;
const int M = 1e5+2;
const int inf = 1e18;
main(){
	int a , b;
	cin >> a >> b;
	if(a <= b) cout <<"unsafe";
	else cout << "safe";
}
