Croatian

#include <cstdio>
#include <algorithm>
#include <string>
#define forn(I,B) for (int I=1;I<=(B);I++)
#define rep(I,B) for (int I=0;I<(B);I++)
#define N 111111
using namespace std;

int s[N],n,a[N],m;
pair<long long,long long> t[N];
long long sorted[N],ans;
char buf[10];

inline void upd(int pos){
    for (;pos<=n;pos=(pos|(pos-1))+1) ++s[pos];
}

inline int get_sum(int pos){
    int res=0;
    for (;pos;pos&=pos-1) res+=s[pos];
    return res;
}

int main(){
    scanf("%d\n",&n);
    forn(i,n){
        gets(buf);
        m=strlen(buf);
        rep(j,m){
            t[i].first=t[i].first*27ll+buf[j]-'a'+1;
            t[i].second=t[i].second*27ll+buf[m-j-1]-'a'+1;
        }
        rep(j,10-m){
            t[i].first*=27ll;
            t[i].second*=27ll;
        }
        sorted[i]=t[i].second;
    }
    sort(t+1,t+n+1);
    sort(sorted+1,sorted+n+1);
    forn(i,n) a[i]=lower_bound(sorted+1,sorted+n+1,t[i].second)-sorted;
    forn(i,n){
        ans+=get_sum(a[i]);
        upd(a[i]);
    }
    printf("%I64d\n",n*1ll*(n-1)/2-ans);
    return 0;
}