import java.util.*;
import java.io.*; //comment out when submitting

public class c {
  // Scanner in = new Scanner(System.in);
  static Scanner in = null;

  public static void main(String[] args) {
    //comment out this part
    try {
      File file = new File("input.txt");
      in = new Scanner(file);
    } catch(FileNotFoundException e) {
      System.out.println("error");
    }

    new c().go();
  }

  private void go() {
    //read the input
    int n = in.nextInt();
    int d = in.nextInt();
    int[] prices = new int[n];
    for(int i = 0; i < n; i++) {
      prices[i] = in.nextInt();
    }

    //initialize dp table
    int[][] dpTable = new int[n][d+1];
    int sum = 0;
    for(int i = 0; i < n; i++) {
      sum = sum + prices[i];
      dpTable[i][0] = round(sum);
    }

    for(int j = 0; j < d + 1; j++) {
      dpTable[0][j] = dpTable[0][0];
    }

    int[][] sumTable = new int[n][n-1];
    for(int i = 0; i < n; i ++) {
      for(int k = 0; k < n-1; k++) {
        sumTable[i][k] = -1;
      }
    }

    for(int j = 1; j < d + 1; j++) {
      for(int i = 1; i < n; i++) {
        int minCost = Integer.MAX_VALUE;
        for(int k = 0; k < i; k++) {
          int cost = 0;
          if(sumTable[i][k] != -1) {
           cost = dpTable[k][j-1] + round(sumTable[i][k]);
          }
          else{
            int restSum = sumUp(prices, k, i);
            cost = dpTable[k][j-1] + round(restSum);
            sumTable[i][k] = restSum;
          }
          if (cost < minCost) {
            minCost = cost;
          }
        }
        dpTable[i][j] = minCost;
      }
    }
    // for(int[] row: dpTable) {
    //   System.out.println(Arrays.toString(row));
    // }
    int result = Integer.MAX_VALUE;
    for(int c: dpTable[n-1]) {
      if(c < result) {
        result = c;
      }
    }
    System.out.println(result);
  }

  private int sumUp(int[] price, int k, int i) {
    int sum = 0;
    for(int j = k + 1; j <= i; j++) {
      sum = sum + price[j];
    }
    return sum;
  }

  private int round(int n) {
    return (n + 5) / 10 * 10;
  }
}