from collections import defaultdict
def Check(X, T):
    N = len(X)
    L = X[0] - T
    R = X[0] + T
    ret = 0
    for i in range(1,N):
        if L <= X[i] - T <= R:
            R = X[i] + T
        else:
            ret += R - L + 1
            L = X[i] - T
            R = X[i] + T
    ret += R - L + 1
    return ret


N,D,T = map(int,input().split())
X = list(map(int,input().split()))
X.sort()
mod = defaultdict(list)
for i in range(N):
    mod[X[i]%D].append(X[i]//D)
ans = 0
for V in mod.values():
    ans += Check(V, T)
print(ans)