from collections import defaultdict
def solution(survey, choices):
    indicators = (('R', 'T'), ('C', 'F'), ('J', 'M'), ('A', 'N'))
    scores = defaultdict(int)
    type = []
    
    for s, c in zip(survey, choices):
        score = c - 4
        scores[s[0]] -= score
        scores[s[1]] += score
    
    for i in indicators:
        if scores[i[1]] > scores[i[0]]:
            type.append(i[1])
            continue
    
        type.append(i[0])
        
    return "".join(type)