n = int(input())
a = list(map(int, input().split()))

x = [0] * 200000

for i in range(n):
    x[a[i] - 1] = x[a[i] - 1] + 1

for i in range(199998):
    j = 199997 - i
    if x[j] > 0:
        x[j] += x[j + 2]
    
ans = n
for i in range(200000):
    if i > 0 and x[i - 1] > 0 and x[i] > 0:
        ans += x[i]
    
print(ans)