#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <cstring>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;

class PalindromizationDiv1 { public:
	static const int INF = 0x3fffffff;
	static const int NOLETTER = 26;

	int getMinimumCost(string word, vector <string> operations) 
	{
		// Cost for changing a character to another
		int cost[27][27];
		for(int a=0; a<27; ++a)
			for(int b=0; b<27; ++b)
				cost[a][b] = (a==b ? 0 : INF);

		for(size_t i=0; i<operations.size(); ++i)
		{
			stringstream cin(operations[i]);
			string cmd; cin >> cmd;

			char a, b; int c;
			if( cmd == "add" )   { cin >> a >> c;      cost[NOLETTER][ a - 'a'] = c; }
			if( cmd == "erase" ) { cin >> a >> c;      cost[ a - 'a'][NOLETTER] = c; }
			if( cmd == "change" ){ cin >> a >> b >> c; cost[ a - 'a'][ b - 'a'] = c; }
		}

		// Warshall-Floyd
		for(int k=0; k<27; ++k)
			for(int i=0; i<27; ++i)
				for(int j=0; j<27; ++j)
					cost[i][j] = min(cost[i][j], cost[i][k]+cost[k][j]);

		// Cost for matching two letters
		int match_cost[27][27];
		for(int i=0; i<27; ++i)
			for(int j=0; j<27; ++j)
			{
				match_cost[i][j] = INF;
				for(int k=0; k<27; ++k)
					match_cost[i][j] = min(match_cost[i][j], cost[i][k]+cost[j][k]);
			}

		// Solve
		memo.clear();
		int r = rec(match_cost, word, 0, word.size()-1);
		return (r>=INF ? -1 : r);
	}

	map<pair<int,int>,int> memo;
	int rec(const int mc[27][27], const string& w, int s, int e)
	{
		// Base case
		if( s >= e )
			return 0;

		// Memoizaion
		const pair<int,int> key(s, e);
		if( memo.count(key) )
			return memo[key];

		// take best
		int result = INF;
		result = min(result, rec(mc, w, s+1, e-1)+mc[w[s]-'a'][w[e]-'a']);
		result = min(result, rec(mc, w, s,   e-1)+mc[NOLETTER][w[e]-'a']);
		result = min(result, rec(mc, w, s+1, e  )+mc[w[s]-'a'][NOLETTER]);
		return memo[key] = result;
	}
};

// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
 { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
 { os << "{ ";
   for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
   os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const int& Expected, const int& Received) {
 bool ok = (Expected == Received);
 if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
 cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END	 verify_case(_, PalindromizationDiv1().getMinimumCost(word, operations));}
int main(){

CASE(0)
	string word = "racecar"; 
	vector <string> operations; 
	int _ = 0; 
END
CASE(1)
	string word = "topcoder"; 
	string operations_[] = {"erase t 1", "erase o 1", "erase p 1", "erase c 1", "erase d 1", "erase e 1", "erase r 1"};
	  vector <string> operations(operations_, operations_+sizeof(operations_)/sizeof(*operations_)); 
	int _ = 5; 
END
CASE(2)
	string word = "topcoder"; 
	string operations_[] = {"erase t 10", "erase o 1", "erase p 1", "erase c 1", "erase d 1", "erase e 1", "erase r 1"};
	  vector <string> operations(operations_, operations_+sizeof(operations_)/sizeof(*operations_)); 
	int _ = 7; 
END
CASE(3)
	string word = "caaaaaab"; 
	string operations_[] = {"change b a 100000", "change c a 100000", "change c d 50000", "change b e 50000", "erase d 50000", "erase e 49999"};
	  vector <string> operations(operations_, operations_+sizeof(operations_)/sizeof(*operations_)); 
	int _ = 199999; 
END
CASE(4)
	string word = "moon"; 
	string operations_[] = {"erase o 5", "add u 7", "change d p 3", "change m s 12", "change n d 6", "change s l 1"};
	  vector <string> operations(operations_, operations_+sizeof(operations_)/sizeof(*operations_)); 
	int _ = -1; 
END
CASE(5)
	string word = "a"; 
	  vector <string> operations;
	int _ = 0; 
END
CASE(6) // killer!
	string word = "az"; 
	string operations_[] = {"add u 1", "change u b 100", "change a b 2"};
	  vector <string> operations(operations_, operations_+sizeof(operations_)/sizeof(*operations_)); 
	int _ = 103; 
END
CASE(7) // killer!
	string word = "az"; 
	string operations_[] = {"add b 1", "change a b 1"};
	  vector <string> operations(operations_, operations_+sizeof(operations_)/sizeof(*operations_)); 
	int _ = 2; 
END
}
// END CUT HERE
