题意就是有n个产品，每个产品p[i]元，包含m个生产关系a[i], b[i], c[i]， 生产1个a[i]产品需要b[i]号c[i]个，问，购买到n号产品需要多少元?

n <= 100, m <= 5000, p[i] <= 10 ^ 15, 1 <= a[i] <= n, 1 <= b[i] <= n - 1, 1 <= c[i] <= 10