#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int,int> P;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

const int INF = (1<<30)-1;
const int MOD = 1e9+7;
const ll LINF = (1ll<<62)-1;

#define REP(i,n) for(int i=0;i<(n);++i)
#define COUT(x) cout<<(x)<<"\n"
#define COUT16(x) cout << fixed << setprecision(16) << (x) << "\n";

int main(){
   int n;cin >> n;
   if(floor(n*1.08)<206)COUT("Yay!");
   else if(floor(n*1.08)==206)COUT("so-so");
   else COUT(":(");
}


/*
これを入れて実行
g++ code.cpp
./a.out
 */
 
#include <iostream>
#include <cstdio>
#include <stdio.h>
#include <vector>
#include <string>
#include <cstring>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <math.h>
#include <tuple>
#include <iomanip>
#include <bitset>
#include <functional>
#include <cassert>
#include <random>

#define all(x) (x).begin(),(x).end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
 
using namespace std;
typedef long long ll;
typedef long double ld;
 
int dy4[4] = {-1, 0, +1, 0};
int dx4[4] = {0, +1, 0, -1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};
 
const long long INF = 1LL << 61;
const ll MOD = 1e9 + 7;
 
bool greaterSecond(const pair<int, int>& f, const pair<int, int>& s){
    return f.second > s.second;
}
 
ll gcd(ll a, ll b){
	if (b == 0)return a;
	return gcd(b, a % b);
}
 
ll lcm(ll a, ll b){
    return a / gcd(a, b) * b;
}

ll conbinationMemo[201][12];

void cmemoInit(){
    rep(i, 201){
        rep(j, 12){
            conbinationMemo[i][j] = -1;
        }
    }
}
 
ll nCr(ll n, ll r){
    if(conbinationMemo[n][r] != -1) return conbinationMemo[n][r];
    if(r == 0 || r == n){
        return 1;
    } else if(r == 1){
        return n;
    }
    return conbinationMemo[n][r] = (nCr(n - 1, r) + nCr(n - 1, r - 1));
}
 
ll nPr(ll n, ll r){
    r = n - r;
    ll ret = 1;
    for (ll i = n; i >= r + 1; i--) ret *= i;
    return ret;
}
//-----------------------ここから-----------
ll n;
vector<string> s;
vector<set<ll>> parents;
int main(void){
    cin >> n;
    s.resize(n);
    vector<string> rs(n, string(n, '0'));
    rep(i, n) cin >> s[i];
    rep(i, n){
        rep(j, n){
            if(s[i][j] == '1'){
                rs[j][i] = '1';
            }
        }
    }

    parents.resize(n);
    rep(i, n){
        queue<ll> q;
        vector<ll> visited(n, 0);
        visited[i] = 1;
        q.push(i);
        parents[i].insert(i);
        while(!q.empty()){
            ll now = q.front();
            q.pop();
            rep(j, n){
                if(visited[j]) continue;
                if(rs[now][j] == '1'){
                    parents[i].insert(j);
                    visited[j] = 1;
                    q.push(j);
                }
            }
        }
    }
    ld ans = 0;
    rep(i, n){
        ans += 1.0 / (ld)parents[i].size();
    }
    cout << fixed << setprecision(10) << ans << endl;
}