//Uva10768
int main(int argc, char const *argv[])
{
while (~scanf("%d%d", &n, &m)) {
memset(mat, 0, sizeof(mat));
for (int i = 0; i < m; i++) {
int a, b;
scanf("%d%d", &a, &b);
if (a == b) continue;
mat[a][b] = mat[b][a] = true;
}
printf("%s\n", planarity() ? "YES" : "NO");
}
return 0;
}
PyObject *wrap_planarity(PyObject *self,PyObject *args)
{
PyObject *cs;
if(!PyArg_ParseTuple(args,"O",&cs))
return NULL;
int natoms = PySequence_Length(cs);
rvec x[natoms];
PyObject2rvec( cs, x, natoms);
real p = planarity(x, natoms);
PyObject *ret;
ret = Py_BuildValue("d",p);
return ret;
}
