Untitled

#include <bits/stdc++.h>

using namespace std;
int c, n, ans1, ans2;
string virus, str, ans_str;
map <string, int> fMap;
int main()
{
    ifstream fin("virus.in");
    ofstream fout("virus.out");
    fin >> c;
    fin >> virus;

    fin >> n;
    while(n--){
        fin >> str;

        if(str.size() != virus.size())
            continue;

        int cnt = 0;
        for(int i = 0; i < str.size(); i++)
            if(str[i] != virus[i])
                cnt++;

        if(cnt != 1)
            continue;

        ans1++;

        fMap[str]++;
        if(ans2 < fMap[str])
            ans_str = str, ans2 = fMap[str];
        else if(ans2 == fMap[str])
        {
            if(ans_str.size() == 0) ans_str = str;
            ans_str = min(ans_str, str);
        }
    }

    if(c == 1) fout << ans1;
    else fout << ans_str;
    return 0;
}