//#pragma GCC optimize "trapv"
#include<bits/stdc++.h>
using namespace std;
typedef long long int lli;
typedef unsigned long long int ulli;
typedef long double ld;
#define S 1000001
#define M 1000000007
#define nl cout<<"\n";
#define er  cout<<"\n***********\n";
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define test lli t;  cin>>t; while(t--)
#define f0(s,a,b) for(lli s=a;s<b;s++)
#define f1(s,a,b) for(lli s=a;s<=b;s++)
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define print(x) cout<< #x <<"=" <<x<<"\n";
#define out(x) cout<<x;
#define  Y cout<<"YES\n";
#define N cout<<"NO\n";

int main()
{
    lli n,k;
    cin>>n>>k;
    if(n>k)
    cout<<"safe";
    else
    cout<<"unsafe";
    nl

}
//a+b=a⊕b+2∗(a &b)
//__builtin_popcount(number)
//cout<<fixed<<setpricision(8)<<output<<"\n";