Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])


def numJudge(arr, num):
    if arr[0] <= num <= arr[1]:
        return 1
    else:
        return 0


def judge(num):
    num += 1
    ctr = 0
    for k in range(M):
        if gate[k][0] <= num <= gate[k][1]:
            ctr += 1
    if ctr == M:
        return 1
    else:
        return 0


ans = map(judge, range(N))
print(sum(list(ans)))


Fixed submission:
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])

gate_min = 0
gate_max = N

for m in range(M):
    if gate[m][0] > gate_min:
        gate_min = gate[m][0]

    if gate[m][1] < gate_max:
        gate_max = gate[m][1]

#print(gate_min, gate_max)
for k in range(N):
    k = k+1
    if gate_min <= k <= gate_max:
        stepper += 1

print(stepper)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])


def numJudge(arr, num):
    if arr[0] <= num <= arr[1]:
        return 1
    else:
        return 0


def judge(num):
    num += 1
    num = [num]*M
    counter = map(numJudge, gate, num)
    if sum(list(counter)) == M:
        return 1
    else:
        return 0


ans = map(judge, range(N))
print(sum(list(ans)))
"""
for i in range(N):
    i += 1
    counter = 0
    for k in gate:
        #print(k, i)
        if k[0] <= i <= k[1]:
            counter += 1
    #print(counter, M)
    if counter == M:
        stepper += 1
"""


Fixed submission:
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])

gate_min = 0
gate_max = N

for m in range(M):
    if gate[m][0] > gate_min:
        gate_min = gate[m][0]

    if gate[m][1] < gate_max:
        gate_max = gate[m][1]

#print(gate_min, gate_max)
for k in range(N):
    k = k+1
    if gate_min <= k <= gate_max:
        stepper += 1

print(stepper)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])


def judge(num):
    num += 1
    counter = 0
    for k in gate:
        if k[0] <= num <= k[1]:
            counter += 1
    if counter == M:
        return 1
    else:
        return 0


ans = map(judge, range(N))
print(sum(list(ans)))
"""
for i in range(N):
    i += 1
    counter = 0
    for k in gate:
        #print(k, i)
        if k[0] <= i <= k[1]:
            counter += 1
    #print(counter, M)
    if counter == M:
        stepper += 1
"""


Fixed submission:
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])

gate_min = 0
gate_max = N

for m in range(M):
    if gate[m][0] > gate_min:
        gate_min = gate[m][0]

    if gate[m][1] < gate_max:
        gate_max = gate[m][1]

#print(gate_min, gate_max)
for k in range(N):
    k = k+1
    if gate_min <= k <= gate_max:
        stepper += 1

print(stepper)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])


def judge(num):
    num += 1
    counter = 0
    for k in gate:
        if k[0] <= num <= k[1]:
            counter += 1
    if counter == M:
        return 1
    else:
        return 0


for ans in map(judge, range(N)):
    stepper += ans
print(stepper)
"""
for i in range(N):
    i += 1
    counter = 0
    for k in gate:
        #print(k, i)
        if k[0] <= i <= k[1]:
            counter += 1
    #print(counter, M)
    if counter == M:
        stepper += 1
"""


Fixed submission:
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])

gate_min = 0
gate_max = N

for m in range(M):
    if gate[m][0] > gate_min:
        gate_min = gate[m][0]

    if gate[m][1] < gate_max:
        gate_max = gate[m][1]

#print(gate_min, gate_max)
for k in range(N):
    k = k+1
    if gate_min <= k <= gate_max:
        stepper += 1

print(stepper)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])


def judge(num):
    num += 1
    counter = 0
    for k in gate:
        if k[0] <= num <= k[1]:
            counter += 1
    if counter == M:
        return 1
    else:
        return 0


for ans in map(judge, range(N)):
    stepper += ans
print(stepper)
"""
for i in range(N):
    i += 1
    counter = 0
    for k in gate:
        #print(k, i)
        if k[0] <= i <= k[1]:
            counter += 1
    #print(counter, M)
    if counter == M:
        stepper += 1
"""


Fixed submission:
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])

gate_min = 0
gate_max = N

for m in range(M):
    if gate[m][0] > gate_min:
        gate_min = gate[m][0]

    if gate[m][1] < gate_max:
        gate_max = gate[m][1]

#print(gate_min, gate_max)
for k in range(N):
    k = k+1
    if gate_min <= k <= gate_max:
        stepper += 1

print(stepper)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())

stepper = 0

gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])

for i in range(N):
    i += 1
    counter = 0
    for k in gate:
        #print(k, i)
        if k[0] <= i <= k[1]:
            counter += 1
    #print(counter, M)
    if counter == M:
        stepper += 1

print(stepper)


Fixed submission:
N, M = map(int, input().split())

stepper = 0
gate = []

for j in range(M):
    gate_1, gate_2 = map(int, input().split())
    gate.append([gate_1, gate_2])

gate_min = 0
gate_max = N

for m in range(M):
    if gate[m][0] > gate_min:
        gate_min = gate[m][0]

    if gate[m][1] < gate_max:
        gate_max = gate[m][1]

#print(gate_min, gate_max)
for k in range(N):
    k = k+1
    if gate_min <= k <= gate_max:
        stepper += 1

print(stepper)