def optimalUtilization(maxTravelDist, forwardRouteList, returnRouteList):
    temp = list()
    result = list()
    for i in range (0, len(forwardRouteList)):
        temp.append(forwardRouteList[i][1])

    for j in range(0, len(returnRouteList)):
        if (maxTravelDist - returnRouteList[j][1]) in temp:
            result.append((temp.index(maxTravelDist-returnRouteList[j][1])+1, returnRouteList[j][0]))

    return result

def main():
    result = optimalUtilization(10000, [[1, 3000], [2, 9000], [3, 7000], [4, 10000]], [[1, 2000], [2, 3000], [3, 4000], [4, 5000]])
    print(result)

if __name__== "__main__":
  main()