// Akshit Awasthi
#include <bits/stdc++.h>
#define int long long
#define ld long double
#define pb push_back
#define pf push_front
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define deb(...) cerr << "[" << #__VA_ARGS__ << ": " << (_VA_ARGS__) << "]\n"
#define deb2(x, y) cerr << #x << " = " << x << "\t" << #y << " = " << y << endl
#define fastio                    \
    std::ios::sync_with_stdio(0); \
    std::cin.tie(NULL);           \
    std::cout.tie(NULL)
#define mod1 1000000007
#define mod2 998244353
#define MAX (int)1e3

using namespace std;

int dist[1001];
bool isgirl[1001];
vector<int> tree[1001];

void dfs(int node, int src, int dis) {
    dist[node] = dis;
    for (int i : tree[node]) {
        if (i != src) {
            dfs(i, node, dis + 1);
        }
    }
}

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

int32_t main(void) {

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