#include<cstdio>
using namespace std;
int a[500010];
int main() {int n,ans = 0;scanf("%d",&n);for(int i = 1; i <= n; i++) {scanf("%d",&a[i]);}for(int i = 1; i <= n; i++)for(int j = i + 1; j <= n; j++)if(a[j] < a[i])ans++;printf("%d",ans);return 0;
}

#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 500010
#define ll long longll a[maxn],n;
ll qwq[maxn];
ll ans;void qsort(ll l,ll r){if(l == r)return ;ll mid = (l + r) >> 1;qsort(l,mid);qsort(mid + 1,r);ll i = l,j = mid + 1,k = l;while(i <= mid && j <= r){//合并操作if(a[i] <= a[j])qwq[k++] = a[i++];elseqwq[k++] = a[j++],ans += mid - i + 1;}while(i <= mid)qwq[k] = a[i],k++,i++;while(j <= r)qwq[k] = a[j],k++,j++;for(ll i = l;i <= r;i++)a[i] = qwq[i];
}//其实归并排序不是很难emmmm多想一想就好啦int main(){scanf("%lld",&n);for(ll i = 1;i <= n;i++)scanf("%lld",&a[i]);qsort(1,n);printf("%lld",ans);return 0;
}

#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 500010
#define ll long longll ans,n;
ll www[maxn];struct Tree{ll num,QAQ,qwq;
}tree[maxn];bool cmp(Tree x,Tree y){return x.QAQ < y.QAQ;
}bool ccmp(Tree x,Tree y){return x.qwq < y.qwq;
}ll lowbit(ll x){return x & (-x);
}void add(ll x){while(x <= n){www[x] ++;x += lowbit(x);}
}ll sum(ll x){ll orz = 0;while(x > 0){orz += www[x];x -= lowbit(x);}return orz;
}int main(){scanf("%lld",&n);for(ll i = 1;i <= n;i++){scanf("%lld",&tree[i].QAQ);tree[i].qwq = i;}sort(tree + 1,tree + n + 1,cmp);for(ll i = 1;i <= n;i++)tree[i].num = i;sort(tree + 1,tree + n + 1,ccmp);for(ll i = n;i >= 1;i--){add(tree[i].num);ans += sum(tree[i].num - 1);}printf("%lld",ans);return 0;
}

#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 500010
#define ll long longll ans,n;
ll www[maxn];struct Tree {ll num,QAQ,qwq;
} tree[maxn];bool cmp(Tree x,Tree y) {return x.QAQ < y.QAQ;
}bool ccmp(Tree x,Tree y) {return x.qwq < y.qwq;
}ll lowbit(ll x) {return x & (-x);
}void add(ll x) {while(x <= n) {www[x] ++;x += lowbit(x);}
}ll sum(ll x) {ll orz = 0;while(x > 0) {orz += www[x];x -= lowbit(x);}return orz;
}//以上，树状数组操作int main() {scanf("%lld",&n);for(ll i = 1; i <= n; i++) {scanf("%lld",&tree[i].QAQ);//QAQ记录原始数据tree[i].qwq = i;//qwq记录输入顺序
    }sort(tree + 1,tree + n + 1,cmp);//排QAQ来进行我那被学长称为独特的离散化操作
// for(ll i = 1;i <= n;i++)// tree[i].num = i;int now = 1;int last = tree[1].QAQ;tree[1].num = 1;for(int i = 1; i <= n; i++) {if(tree[i] .QAQ == last) {tree[i].num = now;continue;}last = tree[i].QAQ;now++;tree[i].num = now;}//这里就是我从40到100的转折点emmmm防止数据重复sort(tree + 1,tree + n + 1,ccmp);//排序qwq使恢复正常输入顺序for(ll i = n; i >= 1; i--) {add(tree[i].num);ans += sum(tree[i].num - 1);}//从后往前依次放到树状数组里然后求和printf("%lld",ans);return 0;
}