#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;
int N, M;
vector<int> adj[100001];
int depth[100001];
bool isCactus = true;
int dfs(int to, int from, int d) {
int numBack = 0;
int ret = depth[to] = d;
for (int i = 0 ; i < adj[to].size(); ++i) {
int next = adj[to][i];
if (next == from) continue;
if (depth[next] != -1 && depth[next] < depth[to]) {
numBack++;
ret = depth[next];
}
if (depth[next] != -1) continue;
int res = dfs(next, to, d + 1);
// printf("res: %d, depth[to]: %d\n", res, depth[to]);
if (res <= depth[to]) {
numBack++;
ret = min(ret, res);
}
}
if (numBack > 1) isCactus = false;
return ret;
}
int main() {
scanf("%d%d", &N, &M);
for (int i = 0; i < M; ++i) {
int x, y;
scanf("%d%d", &x, &y);
adj[x-1].push_back(y-1);
adj[y-1].push_back(x-1);
}
memset(depth, -1, sizeof(depth));
dfs(0, -1, 0);
if (isCactus)
printf("Cactus\n");
else
printf("Not cactus\n");
return 0;
}
