// https://www.hackerrank.com/contests/2014-icpc-northwestern-european-regional-practice

import java.io.*;

public class Solution {

static int MAX_PRODUCT = 2024;

static int MAX_DIVIDER = 64;

private static int [][] dp = new int[MAX_PRODUCT][MAX_DIVIDER];

private static int [] savedSum = new int[MAX_PRODUCT];

public static int min(int a, int b) {

return a < b ? a : b;

}

public static int rounded(int v) {

return ((v + 5) / 10) * 10;

}

public static int calc(int [] price, int n, int d) {

if (n == 0) return 0;

if (d == 0) return rounded(savedSum[n]);

if (dp[n][d] != -1) return dp[n][d];

int res = Integer.MAX_VALUE;

for (int index = 0; index < n; index++) {

dp[index][d-1] = calc(price, index, d-1);

res = min(res, dp[index][d-1] + rounded(savedSum[n] - savedSum[index]));

}

return res;

}

private static void resetData(){

for (int i = 0; i < MAX_PRODUCT; i++)

savedSum[i] = 0;

for (int i = 0; i < MAX_PRODUCT; i++)

for (int j = 0; j < MAX_DIVIDER; j++)

dp[i][j] = -1;

}

public static void main(String[] args) throws IOException {

resetData();

BufferedReader ob = new BufferedReader(new InputStreamReader(System.in));

String [] line = ob.readLine().split(" ");

int product = Integer.parseInt(line[0]);

int divider = Integer.parseInt(line[1]);

line = ob.readLine().split(" ");

int [] array = new int[product];

for (int i = 0; i < product; i++){

array[i] = Integer.parseInt(line[i]);

}

savedSum[0] = 0;

for (int i = 1; i <= product; i++){

if (i==1)

savedSum[i] = array[i-1];

else

savedSum[i] = savedSum[i-1] + array[i-1];

}

int result = calc(array, array.length, divider);

System.out.println(result);

}

private static void printArray(int [] array) {

for (int i = 0; i < array.length; i++)

System.out.println(array[i]);

}

}