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


#include <stdio.h>
#include <string.h>

#define N 2000
#define D 20
#define inf 99999999


int prize[N];
int cost[N+1][D+1];

int min(int i, int j){
    if(i<=j)
        return i;
    else
        return j;
}

int rnd (int p){
    if((p%10)>=5)
        return p-p%10+10;
    else
        return p-p%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++)
        cost[0][i]=0;
    for (i = 0; i <= n; i++)
        for (j = 0; j <= d; j++)
        {	 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;
}