int main(int taskD, char**bapc){
int n, a, b;
scanf("%d %d %d", &n, &a, &b);
node graph[n];
for(int i=0; i<n; i++){
scanf("%d %d %d", &graph[i].left, &graph[i].right, &graph[i].tower);
}
Queue*work = newQueue();//trip
init(n);
push(work, newTrip(newPair(a, b), 0));
while(!empty(work)){
trip p = front(work); pop(work);
if(find(p.first.first) == find(p.first.second))
continue;
int d = p.second;
node a = graph[p.first.first ];
node b = graph[p.first.second];
if(a.tower != b.tower){
printf("%d\n", d);
return 0;
}
dunion(p.first.first, p.first.second);
push(work, newTrip(newPair(a.left, b.left ), d+1));
push(work, newTrip(newPair(a.right, b.right), d+1));
}
puts("indistinguishable");
return 0;
}
dbox diou(box a, box b)
{
float u = box_union(a,b);
float i = box_intersection(a,b);
dbox di = dintersect(a,b);
dbox du = dunion(a,b);
dbox dd = {0,0,0,0};
if(i <= 0 || 1) {
dd.dx = b.x - a.x;
dd.dy = b.y - a.y;
dd.dw = b.w - a.w;
dd.dh = b.h - a.h;
return dd;
}
dd.dx = 2*pow((1-(i/u)),1)*(di.dx*u - du.dx*i)/(u*u);
dd.dy = 2*pow((1-(i/u)),1)*(di.dy*u - du.dy*i)/(u*u);
dd.dw = 2*pow((1-(i/u)),1)*(di.dw*u - du.dw*i)/(u*u);
dd.dh = 2*pow((1-(i/u)),1)*(di.dh*u - du.dh*i)/(u*u);
return dd;
}
void test_dunion()
{
box a = {0, 0, 1, 1};
box dxa= {0+.0001, 0, 1, 1};
box dya= {0, 0+.0001, 1, 1};
box dwa= {0, 0, 1+.0001, 1};
box dha= {0, 0, 1, 1+.0001};
box b = {.5, .5, .2, .2};
dbox di = dunion(a,b);
printf("Union: %f %f %f %f\n", di.dx, di.dy, di.dw, di.dh);
float inter = box_union(a, b);
float xinter = box_union(dxa, b);
float yinter = box_union(dya, b);
float winter = box_union(dwa, b);
float hinter = box_union(dha, b);
xinter = (xinter - inter)/(.0001);
yinter = (yinter - inter)/(.0001);
winter = (winter - inter)/(.0001);
hinter = (hinter - inter)/(.0001);
printf("Union Manual %f %f %f %f\n", xinter, yinter, winter, hinter);
}