from collections import Counter
target = "Kato_Shoko"
n = int(input())
s = input().strip()
target_counter = Counter(target)
s_counter = Counter(s)
for char,cnt in target_counter.items():
    if s_counter.get(char,0) < cnt:
        print("NO")
        exit()

print(f"YES {len(s)-len(target)}")