#include <bits/stdc++.h>
using namespace std;
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
#define ftmx 100005
int ft[ftmx];
void update(int i, int add)
{
while(i>0 && i<ftmx){
ft[i] += add;
i += (i&(-i));
}
}
int sum(int i)
{
int s = 0;
while(i>0){
s += ft[i];
i -= (i&(-i));
}
return s;
}
int sumlr(int l, int r){
return sum(r) - sum(l-1);
}
signed main()
{
FASTIO
int n;
cin>>n;
int a[n+1];
for(int i=1; i<=n; i++){
cin>>a[i];
}
long long ans = 0, mx = 1e5 + 1;
for(int i=1; i<=n; i++){
ans += sumlr(a[i]+1, mx);
update(a[i], 1);
}
cout<<ans<<endl;
}
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