import sys

input=sys.stdin.readline

sys.setrecursionlimit(10**9)

n,t=list(map(int,input().split()))

T=list(map(int,input().split()))

ans=t

for i in range(1,n):

    ans+=min(T[i]-T[i-1],t)

print(ans)
n,t=list(map(int,input().split()))

T=list(map(int,input().split()))

ans=t

for i in range(1,n):

    ans+=min(T[i]-T[i-1],t)

print(ans)
import sys

input = sys.stdin.readline
sys.setrecursionlimit(10**9)
n, t = list(map(int, input().split()))
T = list(map(int, input().split()))
ans = t
for i in range(1, n):
    ans += min(T[i] - T[i - 1], t)
print(ans)

n, t = list(map(int, input().split()))
T = list(map(int, input().split()))
ans = t
for i in range(1, n):
    ans += min(T[i] - T[i - 1], t)
print(ans)

-import sys - -input = sys.stdin.readline -sys.setrecursionlimit(10**9)