문제 링크 https://www.acmicpc.net/problem/1969
num, length = map(int, input().split())
dna_list = [input() for i in range(num)]
result = ''
hp = 0
for i in range(length):
count = {'A': 0, 'C': 0, 'G': 0, 'T': 0} # 알파벳 순서
for j in range(num):
if dna_list[j][i] == 'A':
count['A'] += 1
elif dna_list[j][i] == 'C':
count['C'] += 1
elif dna_list[j][i] == 'G':
count['G'] += 1
elif dna_list[j][i] == 'T':
count['T'] += 1
for k, v in count.items():
if v == max(count.values()):
result += k
break
hp += sum(count.values()) - max(count.values())
print(result, hp, sep='\n')