class SegTree():
    def __init__(self, n, e, ope, lst=[]):
        self.N0 = 2 ** (n - 1).bit_length()
        self.e = e
        self.ope = ope
        self.data = [e] * (2 * self.N0)
        if lst:
            for i in range(n):
                self.data[self.N0 + i] = lst[i]
            for i in range(self.N0 - 1, 0, -1):
                self.data[i] = self.ope(self.data[2 * i], self.data[2 * i + 1])
    
    def f5(self):
        for i in range(self.N0 - 1, 0, -1):
            self.data[i] = self.ope(self.data[2 * i], self.data[2 * i + 1])
                
    def update(self, i, x): #a_iの値をxに更新
        i += self.N0
        self.data[i] = x
        while i > 1:
            i >>= 1
            self.data[i] = self.ope(self.data[2 * i], self.data[2 * i + 1])
    
    def add(self, i, x):
        self.update(i, x + self.get(i))
    
    def query(self, l, r): #区間[l, r)での演算結果
        if r <= l:
            return self.e
            
        res = self.e
        l += self.N0
        r += self.N0
        while l < r:
            if l & 1:
                res = self.ope(res, self.data[l])
                l += 1
            if r & 1:
                r -= 1
                res = self.ope(res, self.data[r])
            l >>= 1
            r >>= 1
        return res
            
    
    def get(self, i): #a_iの値を返す
        return self.data[self.N0 + i]

n = int(input())
plst = list(map(int, input().split()))
e = 0
def ope(x, y):
    return x + y

seg = SegTree(n, e, ope)

ans = 0
for p in plst:
    p -= 1
    ans += seg.query(p, n)
    seg.add(p, 1)
print(ans)