from collections import deque

n, m, f, t, s = map(int, input().split())
d = {}
for i in range(m):
    x, y = map(int, input().split())
    if x not in d:
        d[x] = [y]
    else:
        d[x].append(y)
    if y not in d:
        d[y] = [x]
    else:
        d[y].append(x)
used = [-1 for i in range(n + 1)]
used[s] = 1
queue = deque()
queue.appendleft((0, s))
ss = 0
ll = 0
while len(queue) > 0:
    topx, topy = queue.pop()
    used[topy] = topx
    for i in d[topy]:
        if i == t:
            if (topx + 1) % 2 == 0:
                ss += 1
            else:
                ll += 1
        if used[i] == -1 or used[i] > topx + 1:
            queue.appendleft((topx + 1, i))
        
if ss == 0 or ll == 0:
    if ss != 0:
        print(used[f] + 1)
    else:
        print(used[f])
else:
    print("death")