Buggy python submission (verdict: Runtime Error):
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()
    sentou = [0] * (T[-1] + t + 1)
    
    i = 0
    while i < len(T):
        sentou[T[i]] += 1
        sentou[T[i] + t] -= 1
        i += 1

    j = 1
    while j < len(sentou):
        sentou[j] += sentou[j - 1]
        j += 1

    print(n * t - (sum(sentou) - (sentou.count(1) + len(sentou) - sentou.count(1) - sentou.count(0))))

solve()

Fixed submission:
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()

    ans = 0
    for i in range(len(T) - 1):
        ans += min(t, T[i + 1] - T[i])

    print(ans + t)


solve()

Buggy python submission (verdict: Runtime Error):
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()
    sentou = [0] * (T[-1] + t + 1)
    
    i = 0
    while i < len(T):
        sentou[T[i]] += 1
        sentou[T[i] + t] -= 1
        i += 1

    j = 1
    while j < len(sentou):
        sentou[j] += sentou[j - 1]
        j += 1

    print(n * t - (sum(sentou) - (sentou.count(1) + len(sentou) - sentou.count(1) - sentou.count(0))))

solve()

Fixed submission:
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()

    ans = 0
    for i in range(len(T) - 1):
        ans += min(t, T[i + 1] - T[i])

    print(ans + t)


solve()

Buggy python submission (verdict: Time Limit Exceeded):
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()
    sentou = [0 for _ in range(T[-1] + t + 1)]

    i = 0
    while i < len(T):
        sentou[T[i]] += 1
        sentou[T[i] + t] -= 1
        i += 1

    j = 1
    while j < len(sentou):
        sentou[j] += sentou[j - 1]
        j += 1

    print(n * t - (sum(sentou) - (sentou.count(1) + len(sentou) - sentou.count(1) - sentou.count(0))))

solve()

Fixed submission:
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()

    ans = 0
    for i in range(len(T) - 1):
        ans += min(t, T[i + 1] - T[i])

    print(ans + t)


solve()

Buggy python submission (verdict: Time Limit Exceeded):
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()
    sentou = [0 for _ in range(T[-1] + t + 1)]

    i = 0
    while i < len(T):
        sentou[T[i]] += 1
        sentou[T[i] + t] -= 1
        i += 1

    j = 1
    while j < len(sentou):
        sentou[j] += sentou[j - 1]
        j += 1

    print(n * t - (sum(sentou) - (sentou.count(1) + len(sentou) - sentou.count(1) - sentou.count(0))))

solve()

Fixed submission:
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()

    ans = 0
    for i in range(len(T) - 1):
        ans += min(t, T[i + 1] - T[i])

    print(ans + t)


solve()

Buggy python submission (verdict: Time Limit Exceeded):
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()
    sentou = [0 for _ in range(T[-1] + t + 1)]

    for ele_T in T:
        sentou[ele_T] += 1
        sentou[ele_T + t] -= 1

    for i in range(1, len(sentou)):
        sentou[i] += sentou[i - 1]

    print(n * t - (sum(sentou) - (sentou.count(1) + len(sentou) - sentou.count(1) - sentou.count(0))))

solve()

Fixed submission:
def LI(): return [int(x) for x in input().split(" ")]
def LS(): return [str(x) for x in input().split(" ")]
def ItoS(L): return [str(x) for x in L]
def StoI(L): return [int(c) for c in L]


def solve():
    n, t = LI()
    T = LI()

    ans = 0
    for i in range(len(T) - 1):
        ans += min(t, T[i + 1] - T[i])

    print(ans + t)


solve()