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LongnestPath.cpp
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LongnestPath.cpp
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#include<bits/stdc++.h>
using namespace std;
#define fastio ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define ll long long
typedef pair<int,int> pii;
int n;
bool m[105][105];
int dis[105];
void spfa(int start){
int cur;
bool inq[105];
memset(inq,false,sizeof(inq));
queue<int>my;
my.push(start);
while(!my.empty()){
cur=my.front();
my.pop();
inq[cur]=false;
for(int i=1;i<=n;i++){
if(cur!=i && m[cur][i] && dis[cur]+1 > dis[i]){
dis[i]=dis[cur]+1;
if(!inq[i]){
my.push(i);
inq[i]=true;
}
}
}
}
}
int main(void){
fastio;
int cnt=0;
int a,b;
int start;
while(cin>>n){
if(n==0)break;
memset(m,false,sizeof(m));
memset(dis,0,sizeof(dis));
cin>>start;
while(cin>>a>>b){
if(a==0 && b==0)break;
m[a][b]=true;
}
spfa(start);
int ans=1;
for(int i=1;i<=n;i++){
if(dis[i]>dis[ans])ans=i;
}
printf("Case %d: The longest path from %d has length %d, finishing at %d.\n\n",++cnt,start,dis[ans],ans);
}
}