自己的代码，第五题40%，求a了的大佬指导下。。

m = int(input())
a = int(input())
b = int(input())
n = int(input())
bb = []
for i in range(n):
    bb.append(int(input()))

num = []
for i in range(m+1):
    num.append(0)

for i in range(a):
    # num.append(0)
    num[i] = 0

for i in range(a, b+1):
    num[i] = 1

for i in range(a+1, m+1):
    if i in bb:
        num[i] = 0
    else:
        for j in range(i-b, i-a+1):
                num[i] += (num[j] % (pow(10, 9)+7))
print(num[m])