Buggy python submission (verdict: Time Limit Exceeded):
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n0 + 1))

print("-1")

Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
import heapq

n, m = [int(v) for v in input().split(' ')]

costs = []
links = []
for i in range(n):
    costs.append([-1] * i)
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n0 + 1))

print("-1")

Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
import heapq

n, m = [int(v) for v in input().split(' ')]

costs = []
links = []
for i in range(n):
    costs.append([-1] * i)
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    for n1 in range(n0 + 1, n):
        if (closed & (1 << n1)) != 0:
            break
        heapq.heappush(h, (c0, n1))

print("-1")

Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
import heapq

n, m = [int(v) for v in input().split(' ')]

costs = []
links = []
for i in range(n):
    costs.append([0] * i)
    links.append(set())

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1

    for j in range(l, r):
        for k in range(j + 1, r + 1):
            c0 = costs[k][j]
            if c0 == 0 or c0 > c:
                costs[k][j] = c
                links[k].add(j)


h = []
heapq.heappush(h, (0, n-1))
closed = n
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if closed <= n0:
        continue
    closed = n0
    if n0 == 0:
        print(c0)
        exit()

    for n1 in links[n0]:
        c1 = costs[n0][n1]
        heapq.heappush(h, (c0 + c1, n1))

print("-1")



Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
import heapq

n, m = [int(v) for v in input().split(' ')]

costs = []
links = []
for i in range(n):
    costs.append([0] * i)
    links.append(set())

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1

    for j in range(l, r):
        for k in range(j + 1, r + 1):
            c0 = costs[k][j]
            if c0 == 0 or c0 > c:
                costs[k][j] = c
                links[k].add(j)

h = []
heapq.heappush(h, (0, n-1))

while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if n0 == 0:
        print(c0)
        exit()

    for n1 in links[n0]:
        c1 = costs[n0][n1]
        heapq.heappush(h, (c0 + c1, n1))

print("-1")



Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
n, m = [int(v) for v in input().split(' ')]

costs = []
links = []
for i in range(n):
    costs.append([0] * i)
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1

    for j in range(l, r):
        for k in range(j + 1, r + 1):
            c0 = costs[k][j]
            if c0 == 0 or c0 > c:
                costs[k][j] = c
                links[k].append(j)

import heapq
h = []
closed = 0

heapq.heappush(h, (0, n-1))

while len(h) > 0:
    c0, n1 = heapq.heappop(h)
    if n1 == 0:
        print(c0)
        exit()

    for n2 in links[n1]:
        c1 = costs[n1][n2]
        heapq.heappush(h, (c0 + c1, n2))

print("-1")

Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
n, m = [int(v) for v in input().split(' ')]

costs = []
links = []
for i in range(n):
    costs.append([0] * i)
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1

    for j in range(l, r):
        for k in range(j + 1, r + 1):
            c0 = costs[k][j]
            if c0 == 0 or c0 > c:
                costs[k][j] = c
                links[k].append(j)

import heapq
h = []
closed = 0

heapq.heappush(h, (0, n-1))

while len(h) > 0:
    c0, n1 = heapq.heappop(h)
    closed |= (1 << n1)

    if n1 == 0:
        print(c0)
        exit()

    for n2 in links[n1]:
        if closed & (1 << n2) != 0:
            continue

        c1 = 0
        if n2 < n1:
            c1 = costs[n1][n2]
#        elif n2 > n1:
#            c1 = costs[n2][n1]
#        if c1 > 0:
            heapq.heappush(h, (c0 + c1, n2))

print("-1")

Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
n, m = [int(v) for v in input().split(' ')]

costs = []
links = []
for i in range(n):
    costs.append([0] * i)
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]

    for j in range(l, r):
        j1 = j - 1
        for k in range(j + 1, r + 1):
            k1 = k - 1
            c0 = costs[k1][j1]
            if c0 == 0 or c0 > c:
                costs[k1][j1] = c

                links[k1].append(j1)
                links[j1].append(k1)

import heapq
h = []
closed = 0

heapq.heappush(h, (0, n-1))

while len(h) > 0:
    c0, n1 = heapq.heappop(h)
    closed |= (1 << n1)

    if n1 == 0:
        print(c0)
        exit()

    for i in links[n1]:
        if closed & (1 << i) != 0:
            continue

        c1 = 0
        if i < n1:
            c1 = costs[n1][i]
        elif i > n1:
            c1 = costs[i][n1]
        if c1 > 0:
            heapq.heappush(h, (c0 + c1, i))

print("-1")

Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")

Buggy python submission (verdict: Time Limit Exceeded):
n, m = [int(v) for v in input().split(' ')]

costs = []
for i in range(n):
    costs.append([0] * i)

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]

    for j in range(l, r):
        for k in range(j + 1, r + 1):
            c0 = costs[k - 1][j - 1]
            if c0 == 0 or c0 > c:
                costs[k - 1][j - 1] = c

import heapq
h = []
closed = 0

heapq.heappush(h, (0, n-1))

while len(h) > 0:
    c0, n1 = heapq.heappop(h)
    closed |= (1 << n1)

    if n1 == 0:
        print(c0)
        exit()

    for i in range(n):
        if i == n1:
            continue
        if closed & (1 << i) != 0:
            continue

        c1 = 0
        if i < n1:
            c1 = costs[n1][i]
        elif i > n1:
            c1 = costs[i][n1]
        if c1 > 0:
            heapq.heappush(h, (c0 + c1, i))

print("-1")

Fixed submission:
import heapq

n, m = [int(v) for v in input().split(' ')]

links = []
for i in range(n):
    links.append([])

for i in range(m):
    l, r, c = [int(v) for v in input().split(' ')]
    l -= 1
    r -= 1
    links[r].append((l, c))

h = []
heapq.heappush(h, (0, n-1))
closed = 0
while len(h) > 0:
    c0, n0 = heapq.heappop(h)
    if (closed & (1 << n0)) != 0:
        continue
    closed |= (1 << n0)
    if n0 == 0:
        print(c0)
        exit()

    for n1, c1 in links[n0]:
        if (closed & (1 << n1)) != 0:
            continue
        heapq.heappush(h, (c0 + c1, n1))

    n2 = n0 + 1
    if n2 < n:
        if (closed & (1 << n2)) == 0:
            heapq.heappush(h, (c0, n2))

print("-1")