Buggy python submission (verdict: Runtime Error):
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(max-min+1)
else:
    print(0)

Fixed submission:
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(R-L+1)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a and a<R:
            L =a
        else:
            break
        if R > b and L < b:
            R = b
        else:
            break
if M == i+1:
    print(max-min+1)
else:
    print(0)

Fixed submission:
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(R-L+1)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        min = a
        max = b
        count = 1
    else:
        if min < a && a<max:
            min =a
        if max > b && b >min:
            max = b
if M == i+1:
    print(max-min+1)
else:
    print(0)

Fixed submission:
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(R-L+1)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        min = a
        max = b
        count = 1
    else:
        if min < a && a<max:
            min =a
        else:
            break
    if max > b && b >min:
        max = b
    else:
            break
if M == i+1:
    print(max-min+1)
else:
    print(0)

Fixed submission:
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(R-L+1)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        min = a
        max = b
        count = 1
    else:
        if min < a && a<max:
            min =a
        else:
            break
        if max > b && b >min:
            max = b
        else:
            break
if M == i+1:
    print(max-min+1)
else:
    print(0)


Fixed submission:
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(R-L+1)
else:
    print(0)

Buggy python submission (verdict: Time Limit Exceeded):
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        set = {i for i in range(a,b+1)}
        count = 1
    else:
        set = set & {i for i in range(a,b+1)}
print(len(set))

Fixed submission:
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(R-L+1)
else:
    print(0)

Buggy python submission (verdict: Time Limit Exceeded):
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        set = {i for i in range(a,b+1)}
        count = 1
    else:
        set2 ={i for i in range(a,b+1)}
        set = set & set2
print(len(set))

Fixed submission:
N,M = map(int,input().split())
count = 0
for i in range(M):
    a,b = map(int,input().split())
    if count == 0:
        L = a
        R = b
        count = 1
    else:
        if L < a:
            L =a
            if L>R:
                break
        if R > b:
            R = b
            if R < L:
                break
if M == i+1:
    print(R-L+1)
else:
    print(0)