#include<bits/stdc++.h>
using namespace std;
/*Sawal nahi hone wala phir bhi kar lo ek try*/
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define ll long long
#define db double
#define ld long double
#define rep(i,n) for(ll i=0;i<n;i++)
#define rev(i,n) for(ll i=n;i>=0;i--)
#define rep_a(i,a,n) for(ll i=a;i<n;i++)
#define pb push_back
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(), (v).end()
#define debug(x) do { std::cerr << #x << ": " << x << std::endl; } while (0);
#define debugg(x,y) do { std::cerr << #x << ": " << x << "  "<< #y << ": " << y << std::endl; } while (0);
const long long mod = 1000000007;
typedef vector<ll>              vll;
typedef vector<string>          vstr;
typedef vector<char>            vchar;
typedef vector<pair<ll,ll> >    vpll;
typedef set<ll>                 sll;
typedef set<string>             sstr;
typedef set<pair<ll,ll> >       spll;
typedef map<ll,ll>              mllll;
typedef map<string,ll>          mstrll;
typedef queue<ll>               qll;


ll powMod(ll x,ll y)            {ll p=1; while(y){if(y%2){p=(p*x)%mod;} y/=2; x=(x*x)%mod;} return p;}
ll invMod(ll x)                 {return powMod(x,mod-2);}
ll gcd(ll a, ll b)              {return b == 0 ? a : gcd(b, a % b);}
ll nCr(ll n, ll r)              { if(n<r)return 0;ll nfac = 1;ll dfac = 1;for(ll i=n-r+1;i<=n;i++){nfac = (nfac*i)%mod;}for(ll i=1;i<=r;i++){dfac = (dfac*invMod(i))%mod;}return (nfac*dfac)%mod;}

int solve()
{
    int s,w;
    cin>>s>>w;
    if(s>w)
    {
        cout<<"safe";
    }
        else
        {
            cout<<"unsafe";
        }
        
   return 0;    
}

int main()
{
    fast;
	/* #ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
	#else
	#endif */
	solve();
	/* #ifndef ONLINE_JUDGE
	cout<<"\nTime Elapsed: "<<1.0*clock()/ CLOCKS_PER_SEC <<" Sec\n";
	#endif */
	return 0;
}