#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x)+modulo)%modulo)
#define Inf 1000000000000000


int main() {
	
	int N,K;
	cin>>N>>K;
	
	vector<long long> dp(3*K+1,Inf);
	
	vector<string> S(N);
	vector<long long> C(N);
	
	for(int i=0;i<N;i++)cin>>S[i]>>C[i];
	
	vector<vector<vector<int>>> ind(3,vector<vector<int>>(N,vector<int>()));
	
	for(int i=0;i<N;i++){
		for(int j=0;j<S[i].size();j++){
			if(S[i][j]=='J')ind[0][i].push_back(j);
			else if(S[i][j]=='O')ind[1][i].push_back(j);
			else ind[2][i].push_back(j);
		}
	}
	
	dp[0] = 0;
	
	for(int i=0;i<3*K;i++){
		int x = i/K;
		for(int j=0;j<N;j++){
			int to = min(3*K,i + (int)ind[x][j].size());
			if(to/K==x){
				dp[to] = min(dp[to],dp[i]+C[j]);
			}
			else{
				int now = 0;
				to = i;
				while(true){
					//cout<<now<<endl;
					auto it= lower_bound(ind[to/K][j].begin(),ind[to/K][j].end(),now);
					if(it==ind[to/K][j].end())break;
					now = *it;
					now++;
					to++;
					dp[to] = min(dp[to],dp[i]+C[j]);
					if(to==3*K)break;
				}
			}
		}
	}
	
	if(dp.back()==Inf)cout<<-1<<endl;
	else cout<<dp.back()<<endl;
	
    return 0;
}