#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define ll long long int
#define ff first
#define ss second 
#define S size()
#define mod  998244353
#define mset(a,k) memset(a,k,sizeof(a));
#define fr(i, x, y) for ( ll i = x; i < y;i++)
#define dr(i, x, y) for ( ll i = x; i >= y; i--)
#define all(v) v.begin(), v.end()
#define min3(a, b, c) min(a, min(b, c))
#define max3(a, b, c) max(a, max(b, c))
#define pqueue priority_queue<ll>
#define piqueue priority_queue<ll,vll ,greater<ll>>
#define mapcl map<char,ll>
#define mapll map<ll,ll>
#define mapsl map<string,ll>
#define vi vector<ll>
#define vs vector<string>
#define psi pair<string,ll> 
#define pii pair<ll,ll>
#define piii pair<ll,pii>
#define vii vector<pii>
using namespace std;
void fast(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}  
//----------------------------------------FUNCTIONS------------------------------------- 
vi primes;
void sieve(ll n){
    vector<bool> prime(n+1,true);
    for(ll p = 2; p * p <= n; p++){
        if(prime[p] == true){
            for (ll i = p*2; i <= n; i += p)
                prime[i] = false;
        }
    }
    for (int p = 2; p <= n; p++)
       if(prime[p])
          primes.pb(p);
}

ll modexpo(ll a,ll b)
{
    if(b==0)
    return 1;
    if(b==1)
    return a;
    ll temp=modexpo(a,b/2);
    if(b%2)
    return (temp%mod*temp%mod*a)%mod;
    return (temp%mod*temp%mod)%mod;
}

ll gcd(ll x,ll y )
{
    if(y==0) return x;
    return gcd(y,x%y);
}

ll lcm(ll a, ll b){
    return (a*b)/gcd(a, b);
}

ll logx(ll base, ll num){int cnt=0;while(num!=1){num/=base; ++cnt;}return cnt;}

vi vin(ll n){vi a(n);fr(i, 0, n) cin>>a[i];return a;}

void out(vi a){
    for(int i=0;i<(ll)a.S;i++){
        cout<<a[i]<<' ';
    }
    cout<<'\n';
}
void        in(ll *a, ll n)        {for(ll i=0;i<n;i++)cin>>a[i];}
void out(ll *a,ll n){fr(i,0,n){cout<<a[i]<<" ";}}
void out1(vi v){fr(i,0,(ll)v.S){cout<<v[i]<<" ";}cout<<'\n';}
//----------------------------------------START------------------------------------------- 	
int solve(); 
vector<int> v[1001];
int main()
{
	fast();
	//clock_t start=clock();
	ll t=1;
	//cin>>t;
	while(t--)
	{
		fr(i,0,1001)v[i].clear();
		solve();
	}
	/*cout<<"--------------------------------------------\n";
      cout<<(clock() - start )/(double) CLOCKS_PER_SEC<<'\n';*/
} 
int solve()
{
	ll s,w;
	cin>>s>>w;
	if(w>=s)cout<<"unsafe";
	else cout<<"safe";
  return 0;
}  
