Buggy python submission (verdict: Runtime Error):
def f(A, i, j, k, nex,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in nex:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S[:-1]):
        if S[i+1] == "AB":
            n = [0,1]
        if S[i+1] == "BC":
            n = [2,1]
        if S[i+1] == "AC":
            n = [0,2]
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, n,res)
            else:
                res += f(arr,0,1,2,n,res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, n,res)
            else:
                res += f(arr,1,2,0,n,res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 2,0, 1, n,res)
            else:
                res += f(arr,0,2,1,n,res)
    print("Yes")
    for s in res:
        print(s)
main()

Fixed submission:
def f(A, i, j, k, nex,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in nex:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S[:-1]):
        n = []
        if S[i+1] == "AB":
            n = [0,1]
        if S[i+1] == "BC":
            n = [2,1]
        if S[i+1] == "AC":
            n = [0,2]
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, n,res)
            else:
                res += f(arr,0,1,2,n,res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, n,res)
            else:
                res += f(arr,1,2,0,n,res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 2,0, 1, n,res)
            else:
                res += f(arr,0,2,1,n,res)
    print("Yes")
    for s in res:
        print(s)
main()

Buggy python submission (verdict: Runtime Error):
def f(A, i, j, k, nex,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in nex:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S[:-1]):
        if S[i+1] == "AB":
            n = [0,1]
        if S[i+1] == "BC":
            n = [2,1]
        if S[i+1] == "AC":
            n = [0,2]
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, n,res)
            else:
                res += f(arr,0,1,2,n,res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, n,res)
            else:
                res += f(arr,1,2,0,n,res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 2,0, 1, n,res)
            else:
                res += f(arr,0,2,1,n,res)
    for s in res:
        print(s)
main()

Fixed submission:
def f(A, i, j, k, nex,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in nex:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S[:-1]):
        n = []
        if S[i+1] == "AB":
            n = [0,1]
        if S[i+1] == "BC":
            n = [2,1]
        if S[i+1] == "AC":
            n = [0,2]
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, n,res)
            else:
                res += f(arr,0,1,2,n,res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, n,res)
            else:
                res += f(arr,1,2,0,n,res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 2,0, 1, n,res)
            else:
                res += f(arr,0,2,1,n,res)
    print("Yes")
    for s in res:
        print(s)
main()

Buggy python submission (verdict: Runtime Error):
def f(A, i, j, k, next,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in next:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S[:-1]):
        if S[i+1] == "AB":
            n = [0,1]
        if S[i+1] == "BC":
            n = [2,1]
        if S[i+1] == "AC":
            n = [0,2]
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, n,res)
            else:
                res += f(arr,0,1,2,n,res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, n,res)
            else:
                res += f(arr,1,2,0,n,res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 0, 2, 1, n,res)
            else:
                res += f(arr,2,0,1,n,res)
    for s in res:
        print(s)
main()

Fixed submission:
def f(A, i, j, k, nex,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in nex:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S[:-1]):
        n = []
        if S[i+1] == "AB":
            n = [0,1]
        if S[i+1] == "BC":
            n = [2,1]
        if S[i+1] == "AC":
            n = [0,2]
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, n,res)
            else:
                res += f(arr,0,1,2,n,res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, n,res)
            else:
                res += f(arr,1,2,0,n,res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 2,0, 1, n,res)
            else:
                res += f(arr,0,2,1,n,res)
    print("Yes")
    for s in res:
        print(s)
main()

Buggy python submission (verdict: Runtime Error):
def f(A, i, j, k, next,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in next:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S):
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, S[i+1],res)
            else:
                res += f(arr,0,1,2,S[i+1],res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, S[i+1],res)
            else:
                res += f(arr,1,2,0,S[i+1],res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 0, 2, 1, S[i+1],res)
            else:
                res += f(arr,2,0,1,S[i+1],res)
    for s in res:
        print(s)
main()

Fixed submission:
def f(A, i, j, k, nex,res):
    if A[i] == A[j] == 0:
        print("No")
        exit()
    elif A[i] == A[j] == 1 and A[k] == 0:
        if i in nex:
            A[i] += 1
            A[j] -= 1
            return "ABC"[i]
        else:
            A[i] -= 1
            A[j] += 1
            return "ABC"[j]
    else:
        A[i] += 1
        A[j] -= 1
        return "ABC"[i]
    

def main():
    N, A, B, C = [int(_n) for _n in input().split()]
    S = []
    for i in range(N):
        s = input()
        S.append(s)
    if [A,B,C].count(0) == 3:
        print("No")
        return
    res = ""
    arr = [A,B,C]
    S.append("")
    for i,s in enumerate(S[:-1]):
        n = []
        if S[i+1] == "AB":
            n = [0,1]
        if S[i+1] == "BC":
            n = [2,1]
        if S[i+1] == "AC":
            n = [0,2]
        if s == "AB":
            if arr[0] > arr[1]:
                res += f(arr, 1, 0, 2, n,res)
            else:
                res += f(arr,0,1,2,n,res)
        elif s == "BC":
            if arr[1] > arr[2]:
                res += f(arr, 2, 1, 0, n,res)
            else:
                res += f(arr,1,2,0,n,res)
        elif s == "AC":
            if arr[0] > arr[2]:
                res += f(arr, 2,0, 1, n,res)
            else:
                res += f(arr,0,2,1,n,res)
    print("Yes")
    for s in res:
        print(s)
main()