n,m,s,t=gets.split.map &:to_i
z=10**9
d=(1..n).map{[z]*n}
e=(1..n).map{[z]*n}
m.times{
  u,v,c=gets.split.map &:to_i
  d[u][v]=d[v][u]=e[u][v]=e[v][u]=c
}
n.times{|w|n.times{|u|n.times{|v|
  d[u][u]=0
  d[u][v]=[d[u][v],d[u][w]+d[w][v]].min
}}}
print u=s
(
  print' ',u=(0...n).find{|v|
    d[u][t]==e[u][v]+d[v][t]
  }
)while u!=t