Language: C++

#include <iostream>
#include <ostream>
#include <istream>
#include <cmath>
#include <string>
#include <vector>
#include <sstream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <vector>
#include <set>
#define pb push_back
#define ppb pop_back
using namespace std;
#define forn(i, n) for (int i = 0; i < int(n); i++)
#define for1(i, n) for (int i = 1; i <= int(n); i++)
#define forv(i, v) forn(i, v.size())
#define all(x) x.begin(), x.end()
#define pb push_back
#define mp make_pair
#define CIN_FILE "input.txt"
#define COUT_FILE "output.txt"
#define pi 3.1415926535897932
#define NMAX 100005
#define INF 1000000009
typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;
bool absd[100001][100001];
int ab[100001];
int n;
bool b[100001];
int at[100001];
int v;
int bfs(int t) {
	v=t;
	if(t==0)
		return o;
	int f=1;
	for(int i=0; i<n; i++) {
		if(absd[i][t]==1&&!b[i])f=0,at[v]=++o;
	}
	if(f) {
		b[t]=1;
		v=2,o=0;
		return bfs(1);
	}
}
int check(int y);
{
	int ans=0;
	if(at[y]==0) {
		for(int i=0; i<n; i++) {
			if(absd[i][y]==0&&at[i]==0)ans++,y=i;
		}
	}
	return ans;
}
int main() {
	at[1]=1;
	int n;
	for(int i=0; i<n; i++) {
		int a,b;
		cin>>a>>b;
		if(a>b)
			absd[b][a]=true;
		else
			absd[a][b]=true;
	}
	ab[0]=2;
	ab[1]=3;
	int ast=bfs(2);
	int d1=0,d2=1;
	int q=2,i=0;
	int h=1;
	while(true) {
		if(!i) {
			for(int j=0; j<n; j++) {
				if(absd[j][d1]&&!at[j]&&check(j)>ast-q)cout<<"Fennec",return 0;
			}
			for(int j=0;j<n;j++)
			{
				if(at[j]==q-2&&ab[j]==3&&!check(j))cout<<"Snuke",return 0;
				else if(at[j]==q-2&&ab[j]!=2&&ab[j]!=3)ab[j]=2,i++,q++;
			}
		}
		else{
			for(int j=0; j<n; j++) {
				if(absd[j][d1]&&!at[j]&&check(j)>ast-q)cout<<"Snuke",return 0;
			}
			for(int j=0;j<n;j++)
			{
				if(at[j]==q-2&&ab[j]==3&&!check(j))cout<<"Fennec",return 0;
				else if(at[j]==q-2&&ab[j]!=2&&ab[j]!=3)ab[j]=3,i--,q++;
			}
		}
		if(ast-q==0)h=0,break;
	}
	if(h==0)
	   cout<<"Snuke"
	return 0;
}

Compiler output:
a.cc: In function 'int bfs(int)':
a.cc:44:24: error: 'o' was not declared in this scope
   44 |                 return o;
      |                        ^
a.cc:47:53: error: 'o' was not declared in this scope
   47 |                 if(absd[i][t]==1&&!b[i])f=0,at[v]=++o;
      |                                                     ^
a.cc:51:21: error: 'o' was not declared in this scope
   51 |                 v=2,o=0;
      |                     ^
a.cc: At global scope:
a.cc:56:1: error: expected unqualified-id before '{' token
   56 | {
      | ^
a.cc: In function 'int main()':
a.cc:85:87: error: expected primary-expression before 'return'
   85 |                                 if(absd[j][d1]&&!at[j]&&check(j)>ast-q)cout<<"Fennec",return 0;
      |                                                                                       ^~~~~~
a.cc:89:82: error: expected primary-expression before 'return'
   89 |                                 if(at[j]==q-2&&ab[j]==3&&!check(j))cout<<"Snuke",return 0;
      |                                                                                  ^~~~~~
a.cc:95:86: error: expected primary-expression before 'return'
   95 |                                 if(absd[j][d1]&&!at[j]&&check(j)>ast-q)cout<<"Snuke",return 0;
      |                                                                                      ^~~~~~
a.cc:99:83: error: expected primary-expression before 'return'
   99 |                                 if(at[j]==q-2&&ab[j]==3&&!check(j))cout<<"Fennec",return 0;
      |                                                                                   ^~~~~~
a.cc:103:33: error: expected primary-expression before 'break'
  103 |                 if(ast-q==0)h=0,break;
      |                                 ^~~~~
a.cc:106:25: error: expected ';' before 'return'
  106 |            cout<<"Snuke"
      |                         ^
      |                         ;
  107 |         return 0;
      |         ~~~~~~