x,d = map(float,input().split())
n = int(input())
A = list(map(float,input().split()))
sn1 = x+d
sn2 = x-d
ans = 0;
flag1= 0;
if (A[0] <= x):
    flag1 = 0
    ans+=1
else:
    flag1 = 1
    ans+=1
for i in range (1,n):
    if (flag1 == 0):
        if (A[i] >= sn1):
            flag1 = 1
            ans+=1
        else:
            if (A[i] <= x):
                ans+=1
    else:
        if (A[i] <= sn2):
            flag1 = 0
            ans+=1
        else:
            if (A[i] > x):
                ans+=1
print(n - ans)