#include <iostream>
#include <vector>
using namespace std;
vector<int> vecI;
const int MAX = 100000099;
const int N = 1000;
int len[N];
bool visited[N] = {false};
int ans[N][N];
void dijskstra(int s,int n)
{
for(int i=1;i<=n;++i)
{
if(i!=s)
{
if(len[i]>ans[s][i])
{
len[i] = ans[s][i];
}
}
}
visited[s] = true;
for(int i =1;i<=n;++i)
{
int ti;
for(int i=1;i<=n;++i)
{
if(!visited[i])
{
ti = i;
}
}
for(int j=1;j<=n;++j)
{
if(!visited[j]&&len[j]<len[ti])
{
ti = j;
}
}
visited[ti] = true;
vecI.push_back(ti);
for(int j=1;j<=n;++j)
{
if(!visited[j]&&(len[j]>ans[ti][j]+len[ti]))
{
len[j] = ans[ti][j] + len[ti];
}
}
}
}
int main()
{
int n,m;
cin>>n>>m;
for(int i=1;i<=n;++i)
{
for(int j=1;j<=n;++j)
{
ans[i][j] = MAX;
}
}
for(int i=0;i<m;++i)
{
int s,e,dist;
cin>>s>>e>>dist;
ans[s][e] = dist;
}
int start;
cin>>start;
for(int i=1;i<=n;++i)
{
len[i] = MAX;
}
dijskstra(start,n);
for(int i=0;i<n-1;++i)
{
cout<<vecI[i]<<" "<<len[vecI[i]]<<endl;
}
return 0;
}
#include <vector>
using namespace std;
vector<int> vecI;
const int MAX = 100000099;
const int N = 1000;
int len[N];
bool visited[N] = {false};
int ans[N][N];
void dijskstra(int s,int n)
{
for(int i=1;i<=n;++i)
{
if(i!=s)
{
if(len[i]>ans[s][i])
{
len[i] = ans[s][i];
}
}
}
visited[s] = true;
for(int i =1;i<=n;++i)
{
int ti;
for(int i=1;i<=n;++i)
{
if(!visited[i])
{
ti = i;
}
}
for(int j=1;j<=n;++j)
{
if(!visited[j]&&len[j]<len[ti])
{
ti = j;
}
}
visited[ti] = true;
vecI.push_back(ti);
for(int j=1;j<=n;++j)
{
if(!visited[j]&&(len[j]>ans[ti][j]+len[ti]))
{
len[j] = ans[ti][j] + len[ti];
}
}
}
}
int main()
{
int n,m;
cin>>n>>m;
for(int i=1;i<=n;++i)
{
for(int j=1;j<=n;++j)
{
ans[i][j] = MAX;
}
}
for(int i=0;i<m;++i)
{
int s,e,dist;
cin>>s>>e>>dist;
ans[s][e] = dist;
}
int start;
cin>>start;
for(int i=1;i<=n;++i)
{
len[i] = MAX;
}
dijskstra(start,n);
for(int i=0;i<n-1;++i)
{
cout<<vecI[i]<<" "<<len[vecI[i]]<<endl;
}
return 0;
}