#include using namespace std; int N,M; int map[1230][1230]; bool has(int a, int b) { return map[a][b]; } bool valid(int* q) { int w[4] = {0}; for (int i=0; i<4; i++) { for (int j=0; j<4; j++) { if (i==j) continue; if (has(q[i], q[j])) { w[j]++; } } } for (int i=0; i<4; i++) { if (w[i] != 2) return false; } return true; } int main(){ cin >> N >> M; for (int i=0; i> a >> b; map[a][b] = map[b][a] = true; } int ans = 0; for (int i=0; i