import java.util.Scanner; public class Main{ public long maxNums(String nums, int numsSize, int a, int b, int c){ String module_a="nico", module_b="niconi", module_c="niconiconi"; long [] dp = new long[numsSize+1]; for(int i=0;i<=3;i++)dp[i]=0; for(int i=4;i<=numsSize;i++){ dp[i] = dp[i-1]; if(nums.substring(i-4, i).equals(module_a))dp[i]=Math.max(dp[i-4]+a, dp[i]); if(i>=6 && nums.substring(i-6, i).equals(module_b))dp[i] = Math.max(dp[i-6]+b, dp[i]); if(i>=10 && nums.substring(i-10, i).equals(module_c))dp[i] = Math.max(dp[i-10]+c, dp[i]); } return dp[numsSize]; } public static void main(String [] args){ Scanner in = new Scanner(System.in); int numsSize = in.nextInt(), a = in.nextInt(), b = in.nextInt(), c = in.nextInt(); in.nextLine(); String nums = in.nextLine(); Main m = new Main(); System.out.println(m.maxNums(nums, numsSize, a, b, c)); } }