#include <stdio.h>
int n,k;
int a[10005];
char ch[10005];
void read_solve ()
{
    int i,j;
    scanf ("%d\n",&n);
    gets(ch);
    for (i=1; i<=n; ++i)
        for (j=1; j<i; ++j)
            if (a[i]<a[j])
                ++k;
    printf ("%d",k);
}
int main ()
{
    freopen("litere.in","r",stdin);   
    freopen("litere.out","w",stdout); 
    read_solve ();
    return 0;
}