P1800F2, F2 for failed twice

#include <bits/stdc++.h>
using namespace std;
#define ll long long
int main()
{
    ll n;
    cin>>n;
    pair <ll,string> p[n+1];
    for (ll i=1; i<=n; i++){
        string s;
        cin>>s;
        ll x=s.length();
        map <char,ll> mp;
        for (ll i=0; i<x; i++){
            mp[s[i]]++;
        }
        string y="";
        for (ll i=97; i<=122; i++){
            y += to_string((mp[(char)i]==0)?(0):((mp[(char)i]%2)?(1):(2)));
        }
        // debugger(1)
        // cout<<"x = "<<x<<"\n";
        // cout<<"y = "<<y<<"\n";
        p[i] = make_pair(x,y);
    }
    ll ans=0;
    // cout<<"pairs generated, n^2 iterations begin\n";
    for (ll i=1; i<n; i++){
        for (ll j=i+1; j<=n; j++){
            // debugger(2)
            // cout<<"for the iteration, i = "<<i<<" and j = "<<j<<"\n";
            if ((p[i].first+p[j].first)%2==0) continue;
            // debugger(3)
            // cout<<"odd length right? = "<<(p[i].first+p[j].first)%2<<"\n";
            string s="";
            for (ll k=0; k<26; k++){
                ll z=(p[i].second)[k]-48+(p[j].second)[k]-48;
                s += to_string((z==0)?(0):((z%2)?(1):(2)));
                // debugger(4)
                // cout<<s<<"\n";
            }
            // cout<<"final string = "<<s<<"\n";
            ll e=0, f=0;
            for (ll k=0; k<26; k++){
                if (s[k]-48==0) e++;
                if (s[k]-48==2) f++;
            }
            // debugger(5)
            // cout<<"e = "<<e<<"\n";
            // cout<<"f = "<<f<<"\n";
            if (e==1 && f==0) ans++;
            // cout<<"ans = "<<ans<<"\n";
        }
    }
    cout<<ans;
}