N,T = [int(i) for i in input().split()]

ts = [int(i) for i in input().split()]

ret = 0

# for ind in range (1, N):

#     ret += min(T,ts[ind]-ts[ind-1])

for diff in [ts[ind+1]-ts[ind] for ind in range(N-1)]:

    ret += min(T,diff)

print((ret+T))

N,T = [int(i) for i in input().split()]

ts = [int(i) for i in input().split()]

ret = 0

# for ind in range (1, N):

#     ret += min(T,ts[ind]-ts[ind-1])

for diff in [ts[ind+1]-ts[ind] for ind in range(N-1)]:

    ret += T if T<diff else diff

print((ret+T))

N, T = [int(i) for i in input().split()]
ts = [int(i) for i in input().split()]
ret = 0
# for ind in range (1, N):
#     ret += min(T,ts[ind]-ts[ind-1])
for diff in [ts[ind + 1] - ts[ind] for ind in range(N - 1)]:
    ret += min(T, diff)
print((ret + T))

N, T = [int(i) for i in input().split()]
ts = [int(i) for i in input().split()]
ret = 0
# for ind in range (1, N):
#     ret += min(T,ts[ind]-ts[ind-1])
for diff in [ts[ind + 1] - ts[ind] for ind in range(N - 1)]:
    ret += T if T < diff else diff
print((ret + T))

-    ret += min(T, diff) +    ret += T if T < diff else diff