import copy
n, m = map(int, input().split())
listW = list(input())
s = list(input())
answer = 0
answerList = []
listW2 = copy.deepcopy(listW)
i = 0
for letter in s:
    if letter in listW2:
        i += 1
        answerList.append(letter)
        listW2.remove(letter)
    else:
        i = 0
        listW2 = copy.deepcopy(listW)
        answerList = []
    if i == n:
        answer += 1
        listW2.append(answerList[0])
        answerList.pop(0)
        i -= 1
print(answer)