import sys

input_data = sys.stdin.read().split()
s_len = int(input_data[0])
t_len = int(input_data[1])
k = int(input_data[2])
S = input_data[3]
T = input_data[4]

mask_S = {}
for char in "ACGT":
    valid = [0] * s_len
    
    last = -1000000
    for i in range(s_len):
        if S[i] == char:
            last = i
        if i - last <= k:
            valid[i] = 1
            
    last = 1000000
    for i in range(s_len - 1, -1, -1):
        if S[i] == char:
            last = i
        if last - i <= k:
            valid[i] = 1
            
    b = bytearray((s_len + 7) // 8)
    for i in range(s_len):
        if valid[i]:
            b[i // 8] |= (1 << (i % 8))
            
    mask_S[char] = int.from_bytes(b, byteorder='little')

ans_mask = (1 << (s_len - t_len + 1)) - 1
ans_mask &= mask_S[T[0]]

for j in range(1, t_len):
    ans_mask = (ans_mask << 1) & mask_S[T[j]]

print(ans_mask.bit_count())