//
//  main.cpp
//  ceng
//
//  Created by Haoyang Gu on 15-2-2.
//  Copyright (c) 2015年 Haoyang Gu. All rights reserved.
//

#include <algorithm>
#include <cstdio>
#include <cstring>
using namespace std;

const int N = 2000, D = 20;
const int inf = 99999999;

int Prize[N];
int Cost[N+1][D+1];

int rnd (int p)
{	if(p%10<=4)
      return p-p%10;
    else
      return p-p%10+10;
}

int main()
{	int n, d, i, j, k, s;
    scanf("%d %d\n", &n, &d);
    for (i = 0; i < n; i++)
        scanf("%d", &Prize[i]);
    for (i = 0; i <= n; i++)
        for (j = 0; j <= d; j++)
        {	if (i == 0)
            Cost[i][j] = 0;
        else if (j == 0)
        {	s = 0;
            for (k = 0; k < i; k++)
                s += Prize[k];
            Cost[i][j] = rnd(s);
        }
        else
        {	s = 0;
            Cost[i][j] = inf;
            for (k = i-1; k >= 0; k--)
            {	s += Prize[k];
                Cost[i][j] = min(Cost[i][j], rnd(s) + Cost[k][j-1]);
            }
        }
        }
    printf("%d\n", Cost[n][d]);
    return 0;
}