import argparse
from collections import defaultdict

TRUCK_WEIGHT = 8

def ints(line):
    return tuple(map(int, line.split()))

def parse(stream):
    lines = list(map(ints, stream))
    assert len(lines) > 2
    firstline, weightlines, lastline = lines[0], lines[1:-1], lines[-1]
    assert len(firstline) == 2
    nnodes, nroads = firstline
    assert 1 <= nnodes < nroads
    assert nroads == len(weightlines)
    assert len(lastline) == 1
    goalnode, = lastline
    assert 1 <= goalnode <= nnodes
    def parse_weight(line):
        assert len(line) == 3
        src, dst, weight = line
        assert 1 <= src <= nnodes
        assert 1 <= dst <= nnodes
        assert src != dst
        assert weight > 0
        return src, dst, weight
    weights = defaultdict(dict)
    for src, dst, weight in map(parse_weight, weightlines):
        weights[src][dst] = weight
    return weights, goalnode

def maxroadweight(weights, src, dst, route):
    route = route + [src]
    fromsrc = weights[src]
    if dst not in fromsrc:
        nextweights = set(
            min(nextweight, maxroadweight(weights, nextnode, dst, route))
            for nextnode, nextweight in fromsrc.items()
            if nextnode not in route)
        fromsrc[dst] = max(nextweights) if nextweights else 0
    ans = fromsrc[dst]
    if ans: print(src, "to", dst, "maxweight =", ans)
    return ans

def maxloadweight(weights, goalnode):
    return max(0, maxroadweight(weights, 1, goalnode, []) - TRUCK_WEIGHT)

def description(maxweight):
    return "Max weight = {}".format(maxweight) if maxweight else "No route"

if __name__ == "__main__":
    ap = argparse.ArgumentParser()
    ap.add_argument("file")
    args = ap.parse_args()
    print(description(maxloadweight(*parse(open(args.file)))))