#include<bits/stdc++.h>

#ifdef WIN32
#define outl "%I64d"
#else
#define outl "%lld"
#endif

using namespace std;

typedef long long LL;
const int MAXN = 1000005;
int n, a[MAXN], c[MAXN];
LL ans;

int low_bit(int x){
    return x & -x;
}

void insert(int x){
    while(x < 1000000){
        c[x]++;
        x += low_bit(x);
    }
}

LL query(int x){
    LL res = 0;
    while(x){
        res += c[x];
        x -= low_bit(x);
    }
    return res;
}

int main(){
    scanf("%d", &n);
    for(int i = 1; i <= n; i++)
        scanf("%d", &a[i]);
    for(int i = n; i >= 1; i--){
        ans += query(a[i]);
        insert(a[i]+1);
    }
    printf(outl, ans);
    return 0;
}