int main(){
scanf("%d%d", &noV, &noE);
G = VVI(noV+1, VI(0, 0));
RG = VVI(noV+1, VI(0, 0));
ans = VVI(noV+1, VI(0,0));
vis = VB(noV+1, false);
for(int i = 0 ; i < noE ; i++){
int u,v;
scanf("%d%d", &u, &v);
G[u].push_back(v);
RG[v].push_back(u);
}
for(int i = 1 ; i <= noV ; i++){
if(!vis[i]){
vis[i] = true;
dfs(i);
st.push(i);
}
}
vis = VB(noV+1, false);
vInfoAns = VI(noV+1, -1);
while(!st.empty()){
int here = st.top(); st.pop();
if(!vis[here]){
vis[here] = true;
ans[noAns].push_back(here);
vInfoAns[here] = noAns;
dfsReverse(here);
noAns++;
sort(ans[noAns-1].begin(), ans[noAns-1].end());
}
}
vis = VB(noAns+1, false);
printf("%d\n", noAns);
for(int i = 1 ; i <= noV ; i++){
int here = vInfoAns[i]; // == noAns
if(!vis[here]){
vis[here] = true;
for(auto iter = ans[here].begin() ; iter != ans[here].end() ; iter++){
printf("%d ",*iter);
}
puts("-1");
}
}
return 0;
}
void Graph::topologicalSort(int src, bool *visit, SI &s){
visit[src] = true;
LN::iterator iter = adj[src].begin();
while(iter != adj[src].end()){
if(!visit[(*iter).v]){
topologicalSort((*iter).v, visit, s);
}
iter++;
}
s.push(src);
}
void dfs(int vertex){
for(auto iter = G[vertex].begin() ; iter != G[vertex].end() ; iter++){
int here = *iter;
if(!vis[here]){
vis[here] = true;
dfs(here);
st.push(here);
}
}
return ;
}
int main(int argc, char const *argv[])
{
int n, c, s;
while(SC2(n, k) && n)
{
int lt = 0;
ZERO(in); ZERO(out);
for(int i = 1; i <= n; i++)
{
SC2(c, s);
in[c] = i;
out[s] = i;
lt = max(lt, s+1);
}
while(!p.empty())
p.pop();
int i;
for(i = 1; i < lt; i++)
{
if(out[i]){
if(p.empty() || p.top() != out[i]) break;
else p.pop();
}
if(in[i]){
if((int)p.size() < k) p.push(in[i]);
else break;
}
}
printf("%s\n", i == lt ? "Sim" : "Nao");
}
}