T = int(input())

for case in range(1, T + 1):
    N = int(input())
    distances = list(map(int, input().split()))

    # Menggunakan pendekatan greedy dengan menghitung jarak minimum
    total_distance = 0
    for i in range(N-1):
        total_distance += min(distances[i], distances[i+1])

    print("Case #{}: {:.6f}".format(case, total_distance))