def ReadFile():
    for Line in open("data5.txt"):
        for Part in Line.split():
            yield Part
            
Next = ReadFile().next

def WriteLine(Line):
    open("out5.txt","a").write(str(Line) + "\n")


for QQ in xrange(5):
    N = int(Next())
    Input = []
    
    Paths = dict()
    
    P = set()
    for RR in xrange(N):

        
        From = Next()
        To = Next()
        Cost = int(Next())
        
        P.add(From)
        P.add(To)
        Input.append((From,To,Cost))
        
    for A in P:
        Paths[A] = dict()
        for B in P:
            Paths[A][B] = 9999999
            
    for From,To,Cost in Input:
        Paths[From][To] = Cost
        
    for B in P:
        for A in P:
            for C in P:
                Paths[A][C] = min(Paths[A][C],Paths[A][B] + Paths[B][C])
                
    WriteLine(Paths["YYZ"]["SEA"])