// BEGIN CUT HERE

 /*

  * Author:  plum rain

  * score :

  */

 /*

  */

 // END CUT HERE

 #line 11 "DNAString.cpp"

 #include <sstream>

 #include <stdexcept>

 #include <functional>

 #include <iomanip>

 #include <numeric>

 #include <fstream>

 #include <cctype>

 #include <iostream>

 #include <cstdio>

 #include <vector>

 #include <cstring>

 #include <cmath>

 #include <algorithm>

 #include <cstdlib>

 #include <set>

 #include <queue>

 #include <bitset>

 #include <list>

 #include <string>

 #include <utility>

 #include <map>

 #include <ctime>

 #include <stack>

 using namespace std;

 #define clr0(x) memset(x, 0, sizeof(x))

 #define clr1(x) memset(x, -1, sizeof(x))

 #define pb push_back

 #define sz(v) ((int)(v).size())

 #define all(t) t.begin(),t.end()

 #define zero(x) (((x)>0?(x):-(x))<eps)

 #define out(x) cout<<#x<<":"<<(x)<<endl

 #define tst(a) cout<<a<<" "

 #define tst1(a) cout<<#a<<endl

 #define CINBEQUICKER std::ios::sync_with_stdio(false)

 typedef vector<int> VI;

 typedef vector<string> VS;

 typedef vector<double> VD;

 typedef pair<int, int> pii;

 typedef long long int64;

 const double eps = 1e-;

 const double PI = atan(1.0)*;

 const int inf =  / ;

 string s;

 int d[];

 string temp = "ACTG";

 int gao(int x)

 {

     int ret = ;

     for (int i = ; i < x; ++ i){

         clr0 (d);

         int j = i;

         while (j < sz(s)){

             for (int t = ; t < ; ++ t)

                 if (temp[t] == s[j]) ++ d[t];

             j += x;

         }

         int ma = , sum = ;

         for (int k = ; k < ; ++ k)

             ma = max(ma, d[k]), sum += d[k];

         ret += sum - ma;

     }

     return ret;

 }

 class DNAString

 {

     public:

         int minChanges(int m, vector<string> dna){

             s = accumulate(dna.begin(), dna.end(), string(""));

             int ans = inf;

             for (int i = ; i <= m; ++ i) ans = min(ans, gao(i));

             return ans;

         }

 // BEGIN CUT HERE

     public:

     void run_test(int Case) { if ((Case == -) || (Case == )) test_case_0(); if ((Case == -) || (Case == )) test_case_1(); if ((Case == -) || (Case == )) test_case_2(); if ((Case == -) || (Case == )) test_case_3(); if ((Case == -) || (Case == )) test_case_4(); }

     private:

     template <typename T> string print_array(const vector<T> &V) { ostringstream os; os << "{ "; for (typename vector<T>::const_iterator iter = V.begin(); iter != V.end(); ++iter) os << '\"' << *iter << "\","; os << " }"; return os.str(); }

     void verify_case(int Case, const int &Expected, const int &Received) { cerr << "Test Case #" << Case << "..."; if (Expected == Received) cerr << "PASSED" << endl; else { cerr << "FAILED" << endl; cerr << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } }

     void test_case_0() { int Arg0 = ; string Arr1[] = {"ATAGATA"}; vector <string> Arg1(Arr1, Arr1 + (sizeof(Arr1) / sizeof(Arr1[]))); int Arg2 = ; verify_case(, Arg2, minChanges(Arg0, Arg1)); }

     void test_case_1() { int Arg0 = ; string Arr1[] = {"ACGTGCA"}; vector <string> Arg1(Arr1, Arr1 + (sizeof(Arr1) / sizeof(Arr1[]))); int Arg2 = ; verify_case(, Arg2, minChanges(Arg0, Arg1)); }

     void test_case_2() { int Arg0 = ; string Arr1[] = {"ACGCTGACAGATA"}; vector <string> Arg1(Arr1, Arr1 + (sizeof(Arr1) / sizeof(Arr1[]))); int Arg2 = ; verify_case(, Arg2, minChanges(Arg0, Arg1)); }

     void test_case_3() { int Arg0 = ; string Arr1[] = {"AAAATTTCCG"}; vector <string> Arg1(Arr1, Arr1 + (sizeof(Arr1) / sizeof(Arr1[]))); int Arg2 = ; verify_case(, Arg2, minChanges(Arg0, Arg1)); }

     void test_case_4() { int Arg0 = ; string Arr1[] = {"ACGTATAGCATGACA","ACAGATATTATG","ACAGATGTAGCAGTA","ACCA","GAC"}; vector <string> Arg1(Arr1, Arr1 + (sizeof(Arr1) / sizeof(Arr1[]))); int Arg2 = ; verify_case(, Arg2, minChanges(Arg0, Arg1)); }

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 };

 // BEGIN CUT HERE

 int main()

 {

 //    freopen( "a.out" , "w" , stdout );

     DNAString ___test;

     ___test.run_test(-);

        return ;

 }

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