python，实在不知道哪里错了

q = int(input())
s = input()
for i in range(q):
    n = list(input().split())
    if str(n[0]) == '1':
        s = s + str(n[1])
        print(s)
    elif str(n[0]) == '2':
        s = s[int(n[1]):int(n[1]) + int(n[2]) + 1]
        print(s)
    elif str(n[0]) == '3':
        s = list(s)
        s.insert(int(n[1]), n[2])
        s = ''.join(s)
        print(s)
    elif str(n[0]) == '4':
        s = str(s)
        if str(n[1]) in str(s):
            s = s.find(str(n[1]))
            print(s)
        else:
            print(-1)