#if __has_include("debug.h")
    #include "debug.h"
#else  
#include <bits/stdc++.h>
using namespace std;
#define track  1;
#define d(...) 2;
#endif

#define int long long int

#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl "\n"      

#define all(c) (c).begin(),(c).end()
#define rall(c) (c).rbegin(),(c).rend()
#define ff first
#define ss second
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)

#define gcd(a,b)            __gcd((a),(b))
#define lcm(a,b)            ((a*b)/gcd(a,b))

void solve();

int32_t main()
{
    #ifdef DEBUG
	freopen("input.txt","r",stdin);
	freopen("output.txt","w",stdout);
    #endif 

    fast
    
    int t = 1;
	// cin>>t;
	
	while(t--)
	    solve();
	return 0;  
}

void solve()
{
	int i,j,cnt=0;
	bool flag=0;
	int a,b;
	cin>>a>>b;

	if(a>b)
	{
		cout<<"safe"<<endl;
	}
	else
	{
		cout<<"unsafe"<<endl;
	}

	

}