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

odd = []
even = []
for i in range(n):
    if a[i] % 2 == 1:
        odd.append(a[i])
    else:
        even.append(a[i])

odd = sorted(odd)
even = sorted(even)
odd.append(2e18 - 1)
even.append(2e18)

oddacc = [1] * len(odd)
for i in range(1, len(odd)):
    j = len(odd) - i - 1
    if odd[j] + 2 == odd[j + 1]:
        oddacc[j] += oddacc[j + 1]

evenacc = [1] * len(even)
for i in range(1, len(even)):
    j = len(even) - i - 1
    if even[j] + 2 == even[j + 1]:
        evenacc[j] += evenacc[j + 1]
    
ans = n
it = 0
for i in range(len(odd) - 1):
    while odd[i] >= even[it]:
        it += 1
    if odd[i] + 1 == even[it]:
        ans += evenacc[it]

it = 0
for i in range(len(even) - 1):
    while even[i] >= odd[it]:
        it += 1
    if even[i] + 1 == odd[it]:
        ans += oddacc[it]

print(ans)