import sys,collections,bisect,operator
def MillerRabin_64bit(x):
    if x <= 1:
        return False
    if x == 2:
        return True
    if x % 2 == 0:
        return False
    if x < 1 << 30:
        test = [2, 7, 61]
    else:
        test = [2,325,9375,28178,450775,9780504,1795265022]
    s = 0
    d = x - 1
    while d & 1 == 0:
        s += 1
        d >>= 1
    for i in test:
        if x <= i:
            return True
        y = pow(i,d,x)
        if y == 1 or y == x - 1:
            continue
        c = 0
        for j in range(s-1):
            y = y * y % x
            if y == x - 1:
                c = 1
                break
        if not c:
            return False
    return True
def eratosthenes(n):
    is_prime = [False, False] + [True] * (n-1)
    for p in range(2, n+1):
        if not(is_prime[p]):
            continue
        for k in range(p*2, n+1, p):
            is_prime[k] = False
    return is_prime
#https://github.com/shakayami/ACL-for-python/blob/master/segtree.py
class segtree():
    n=1
    size=1
    log=2
    d=[0]
    op=None
    e=10**15
    def __init__(self,V,OP,E):
        self.n=len(V)
        self.op=OP
        self.e=E
        self.log=(self.n-1).bit_length()
        self.size=1<<self.log
        self.d=[E for i in range(2*self.size)]
        for i in range(self.n):
            self.d[self.size+i]=V[i]
        for i in range(self.size-1,0,-1):
            self.update(i)
    def set(self,p,x):
        assert 0<=p and p<self.n
        p+=self.size
        self.d[p]=x
        for i in range(1,self.log+1):
            self.update(p>>i)
    def get(self,p):
        assert 0<=p and p<self.n
        return self.d[p+self.size]
    def prod(self,l,r):
        assert 0<=l and l<=r and r<=self.n
        sml=self.e
        smr=self.e
        l+=self.size
        r+=self.size
        while(l<r):
            if (l&1):
                sml=self.op(sml,self.d[l])
                l+=1
            if (r&1):
                smr=self.op(self.d[r-1],smr)
                r-=1
            l>>=1
            r>>=1
        return self.op(sml,smr)
    def all_prod(self):
        return self.d[1]
    def max_right(self,l,f):
        assert 0<=l and l<=self.n
        assert f(self.e)
        if l==self.n:
            return self.n
        l+=self.size
        sm=self.e
        while(1):
            while(l%2==0):
                l>>=1
            if not(f(self.op(sm,self.d[l]))):
                while(l<self.size):
                    l=2*l
                    if f(self.op(sm,self.d[l])):
                        sm=self.op(sm,self.d[l])
                        l+=1
                return l-self.size
            sm=self.op(sm,self.d[l])
            l+=1
            if (l&-l)==l:
                break
        return self.n
    def min_left(self,r,f):
        assert 0<=r and r<=self.n
        assert f(self.e)
        if r==0:
            return 0
        r+=self.size
        sm=self.e
        while(1):
            r-=1
            while(r>1 and (r%2)):
                r>>=1
            if not(f(self.op(self.d[r],sm))):
                while(r<self.size):
                    r=(2*r+1)
                    if f(self.op(self.d[r],sm)):
                        sm=self.op(self.d[r],sm)
                        r-=1
                return r+1-self.size
            sm=self.op(self.d[r],sm)
            if (r& -r)==r:
                break
        return 0
    def update(self,k):
        self.d[k]=self.op(self.d[2*k],self.d[2*k+1])
    def __str__(self):
        return str([self.get(i) for i in range(self.n)])
input = sys.stdin.readline
n = int(input())
a = list(map(int,input().split()))
b = []
for i in a:
    b.append(i)
    b.append(i+i)
b = list(set(b))
b.sort()
d = {b[i]:i for i in range(len(b))}
cnt = [0 for i in range(len(b))]
st = segtree(cnt,operator.add,0)
for i in a:
    cnt[d[i]] += 1
    st.set(d[i],st.get(d[i])+1)
ans = 0
c = list(set(a))
for i in c:
    x = cnt[d[i]] * (cnt[d[i]]-1)//2
    st.set(d[i],0)
    y = st.prod(0,d[2*i])
    st.set(d[i],cnt[d[i]])
    ans += x * y
print(ans)