B"Nick's company employed n people. Now Nick needs to build a tree hierarchy of xc2 xabsupervisor-surbodinate xc2 xbb relations in the company (this is to say that each employee, except one, has exactly one supervisor). There are m applications written in the following form: xc2 xabemployee ai is ready to become a supervisor of employee bi at extra cost ci xc2 xbb. The qualification qj of each employee is known, and for each application the following is true: qai xe2 x80 x89> xe2 x80 x89qbi. Would you help Nick calculate the minimum cost of such a hierarchy, or find out that it is impossible to build it. The first input line contains integer n (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891000) -- amount of employees in the company. The following line contains n space-separated numbers qj (0 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89qj xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89106) -- the employees' qualifications. The following line contains number m (0 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89m xe2 x80 x89 xe2 x89 xa4 xe2 x80 x8910000) -- amount of received applications. The following m lines contain the applications themselves, each of them in the form of three space-separated numbers: ai, bi and ci (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89ai, xe2 x80 x89bi xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n, 0 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89ci xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89106). Different applications can be similar, i.e. they can come from one and the same employee who offered to become a supervisor of the same person but at a different cost. For each application qai xe2 x80 x89> xe2 x80 x89qbi. Output the only line -- the minimum cost of building such a hierarchy, or -1 if it is impossible to build it. In the first sample one of the possible ways for building a hierarchy is to take applications with indexes 1, 2 and 4, which give 11 as the minimum total cost. In the second sample it is impossible to build the required hierarchy, so the answer is -1."...