n = int(input())
a = [i for i in map(int, input().split())]
ans = 0

def mex(a,b):
    if a != 1 and b != 1:
        return 1
    if a == 1 and b == 1:
        return 2
    if a == 1 or b == 1 and abs(a-b) == 1:
        return 3
    if a == 1 or b == 1 and abs(a-b) >= 2:
        return 2
    

for i in range(1,n):
    for j in range(i+1,n+1):
        ans += mex(a[i-1],a[j-1])
        
print(ans)