#include<bits/stdc++.h>
using namespace std;
using namespace std::chrono; 
#define ll long long
#define fo(i,v,e) for(v=i;v<e;v++)
#define pb(x) push_back(x)
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fi first 
#define se second
#define all(x) x.begin(),x.end()
#define vi vector<int>
#define vl vector<ll>
#define sz(x) (int)x.size()
#define ull unsigned long long
#define vvi vector<vi>
#define vvl vector<vl>
#define vpi vector<pii>
#define vpl vector<pll>
ll mod = 1000000007;
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
 
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define deb(x...) cerr << "[" << #x << "] = ["; _print(x);
#else
#define deb(x...)
#endif
vector<ll> sieveOfErthnosis(ll n)
{
    vector<bool>flag(n+5,false);
    vector<ll>primes;
    for(int i=2;i*i<=n;i++)
    {
        if(!flag[i])
        {
            for(int j=i*i;j<=n;j+=i)
            {flag[j]=true;}
        }
    }
    for (int  i = 2; i < n+1; i++)
    {
        if(!flag[i])primes.pb(i);
    }
    return primes;
}
void init()
{
    
}
void solve()
{
    ll s,w;cin>>s>>w;
    cout<<(s>w?"safe":"unsafe");
}
int main()
{
    init();
    #ifndef ONLINE_JUDGE
    // freopen("input.txt","r",stdin);
    // freopen("output.txt","w",stdout);
    #endif
    auto start = high_resolution_clock::now(); 
    int T = 1;
    // cin>>T;
    while(T--)
    {
        solve();
    }
    auto stop = high_resolution_clock::now(); 
    auto duration = duration_cast<milliseconds>(stop - start); 
    #ifndef ONLINE_JUDGE
    // cout << "time taken : "<<duration.count()<<" ms" << endl;
     #endif
}
