 #include <bits/stdc++.h>
#define SpeeD ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define ll long long
#define endl '\n'
//pair<int, int> *p=new pair<int, int>[n];
//std::vector<pair<int,int>> vp;
//v.push_back(make_pair(x,y))
//pair<int, int> p[1000001];
//string *s=new string [n];
//int freq[e];
//freq[a[i]-'a']++; freq[a[i]]++;
 using namespace std;
ll n,t,m,c1,c2,c,x,y,sum,mn=999999999,avg,pos,dif,j,dis,mx,xi,yi,q;
vector<ll>v;
set<ll>s;
map<ll , ll >mp;
bool PE(int x)
{
for (int i=2;i*i<=x;i++)
if (x%i==0)
return false;
return true;
}
bool PR(string s)
{
int n=s.length();
for(int i=0;i<n/2;i++)
if(s[i]!=s[n-i-1])
return false;
return true;
}

int main(void)
{ SpeeD;
cin>>n>>m;
if (n>=m)cout<<"safe";
else cout<<"unsafe";
}
