#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <sstream>
#include <numeric>
#include <iterator>
#include <queue>
#include <set>
#include <map>
#include <vector>
#define mp make_pair
#define pb push_back
#define sqr(x) ((x)*(x))
#define foreach(it,c) for(typeof((c).begin()) it = (c).begin(); it != (c).end(); ++it)
using namespace std;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int,int> PII;
template<typename T> int size(const T &a) { return a.size(); }
int N,M;
VVI links;
int depth[100005];
bool ret = false;
int go(int a, int b, int d) {
depth[a] = d;
int cnt = 0;
int mind = d;
for(int i=0;i<size(links[a]);i++) {
int np = links[a][i];
if(np == b) continue;
// cout << a << " " << np << " (" << b << ") " << cnt << endl;
if(depth[np] != -1 && depth[np] < d) {
mind = depth[np];
cnt++;
}
if(depth[np] != -1) {
continue;
}
int tmp = go(np, a, d+1);
if(tmp <= d) cnt++;
mind = min(mind, tmp);
}
if(cnt > 1) {
// cout << a << " " << b << " " << d << endl;
ret = true;
}
return mind;
}
int main(void)
{
scanf("%d %d", &N, &M);
links.resize(N+1);
for(int i=0;i<M;i++) {
int a,b;
scanf("%d %d", &a, &b);
links[a].pb(b);
links[b].pb(a);
}
memset(depth, -1, sizeof(depth));
go(1, -1, 0);
if(ret) {
cout << "Not cactus" << endl;
} else {
cout << "Cactus" << endl;
}
return 0;
}
