t = int(input())

for i in range(t):
    n = int(input())
    s = "-" + input().rstrip()
    d = []
    for i in range(1,n+1):
        if s[i] == "-": continue
        if s[i-1] == "-":
            d.append([s[i]])
        else:
            d[-1].append(s[i])
    
    k = 0
    p = 0
    for i in range(len(d)):
        k += d[i][0] == "K" and d[i][-1] == "K"
        p += d[i][0] == "P" and d[i][-1] == "P"
    
    if p > k:
        print("P")
    else:
        print("K")