import java.util.*;
public class c {
	Scanner in=new Scanner(System.in);
	public static void main(String[] args) {
		new c().go();
	}
	private void go() {
		int n=in.nextInt(),d=in.nextInt();
		int[] p=new int[n+1];
		for(int i=0;i<n;i++)p[i]=in.nextInt();
		int[][] dp=new int[n+1][d+1];
		int total=0;
		for(int i=n-1;i>=0;i--){//price with no dividers is just price of remaining items
			total+=p[i];
			dp[i][0]=round(total);
		}
		for(int i=1;i<=d;i++)for(int j=0;j<=n;j++){//for this number of items remaining
			int sum=0;
			dp[j][i]=Integer.MAX_VALUE;
			for(int k=j;k<=n;k++){
				dp[j][i]=Math.min(dp[j][i], round(sum)+dp[k][i-1]);//simulate placing the divider at every location
				sum+=p[k];
			}
		}
		System.out.println(dp[0][d]);
	}
	private int round(int total) {
		int mod=total%10;
		if(mod<5)return total-mod;
		return total-mod+10;
	}
}
//cent savings
//with so many products and dividers checking out rounding to nearest 10, figure out least amount of money
//dp