/*
********************
Author : MIHIR ARORA
********************
*/
#include <bits/stdc++.h>
using namespace std;
#define fast cin.tie(NULL); cout.tie(NULL); 
#define input int n; scanf("%d",&n); int*arr = new int[n];  for(int i=0;i<n;i++) scanf("%d",&arr[i]);  
#define inputs int n; scanf("%d",&n); char str[n];   cin>>str;   

typedef long long int ll;
const int mod=1e9+7; 
ll add(ll a, ll b)
{
    return (a%mod+b%mod)%mod;
}

ll mul(ll a, ll b)
{
    return ((a%mod)*(b%mod))%mod;
}

ll sub(ll a, ll b)
{
    return ((a%mod) - (b%mod))%mod;
}
inline void solve()
{
 input; 
}
int main()
{ 
    fast; 
    int n; 
    int s; 
    cin>>n>>s;
    if(n<=s)
        cout<<"unsafe"; 
    else
        cout<<"safe"; 
    
}