Buggy python submission (verdict: Runtime Error):
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if a[i+1][0] != a[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")
    


Fixed submission:
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if l[i+1][0] != l[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")

Buggy python submission (verdict: Runtime Error):
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if a[i+1][0] != a[i][-1]:
            print("No")
            break
    print("Yes")
else:
    print("No")
    


Fixed submission:
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if l[i+1][0] != l[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")

Buggy python submission (verdict: Runtime Error):
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(1, N):
        if a[i][0] != a[i-1][-1]:
            print("No")
            break
    print("Yes")
else:
    print("No")
    


Fixed submission:
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if l[i+1][0] != l[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")

Buggy python submission (verdict: Runtime Error):
N = int(input())
l = list()

for n in range(0,N-1):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(1, N):
        if a[i][0] != a[i-1][-1]:
            print("No")
            break
    print("Yes")
else:
    print("No")
    

Fixed submission:
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if l[i+1][0] != l[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")

Buggy python submission (verdict: Runtime Error):
N = int(input())
l = list()
al = list()
bl = list()
 
for n in range(0,N):
    a = input()
　 l.append(a)
    al.append(a[1])
    bl.append(a[-1])
 
l_unq = list(set(l))
if len(l) == len(l_unq):
    for i in range(0,N-1):
        if al[i+1] != bl[i]:
          print("No")
          break
     print("Yes")
else:
    print("No")


Fixed submission:
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if l[i+1][0] != l[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")

Buggy python submission (verdict: Runtime Error):
N = int(input())
l = list()
al = list()
bl = list()
 
for n in range(0,N):
    a = input()
　 l.append(a)
    al.append(a[:1])
    bl.append(a[-1:])
 
l_unq = list(set(l))
if len(l) == len(l_unq):
    for i in range(0,N-1):
        if al[i+1] != bl[i]:
          print("No")
          break
     print("Yes")
else:
    print("No")

Fixed submission:
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if l[i+1][0] != l[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")

Buggy python submission (verdict: Runtime Error):
N = int(input())
l = list()
al = list()
bl = list()

for n in N:
    a = input()
　 l.append(a)
    al.append(a[:1])
    bl.append(a[-1:])

l_unq = list(set(l))
if len(l) == len(l_unq):
    for i in N-1:
        if al[i+1] != bl[i]:
          print("No")
          break
     print("Yes")
else:
    print("No")

Fixed submission:
N = int(input())
l = list()

for n in range(N):
    a = input()
    l.append(a)

l_uniq = list(set(l))

if len(l) == len(l_uniq):
    for i in range(0, N-1):
        if l[i+1][0] != l[i][-1]:
            print("No")
            break
    else:
        print("Yes")
else:
    print("No")