#include <cstdio>
#include <vector>
using namespace std;
bool ret = true;
bool colp[100005], vis[100005];
int par[100005];
vector<int> graph[100005];
void dfs(int x, int pa){
vis[x] = 1;
par[x] = pa;
for(auto &i : graph[x]){
if(i == pa) continue;
if(!vis[i]) continue;
int pos = x;
while(1){
if(colp[pos]){
ret = 0;
break;
}
colp[pos] = 1;
if(pos == i) break;
pos = par[pos];
}
}
for(auto &i : graph[x]){
if(i == pa) continue;
if(vis[i]) continue;
dfs(i, x);
}
}
int main(){
int n, m;
scanf("%d %d",&n,&m);
for(int i=0; i<m; i++){
int u, v;
scanf("%d %d",&u,&v);
graph[u].push_back(v);
graph[v].push_back(u);
}
dfs(1, 0);
puts(ret ? "Cactus" : "Not cactus");
}
