/*
 * Solution Template for Backpacking
 * 
 * Australian Informatics Olympiad 2024
 * 
 * This file is provided to assist with reading and writing of the input
 * files for the problem. You may modify this file however you wish, or
 * you may choose not to use this file at all.
 */

#include <stdio.h>

/* N is the number of towns. */
int N;

/* K is the maximum number of cans that Norman can fit in his backpack. */
int K;

/*
 * D contains the distances between the towns. Note that the array starts from
 * 0, and so the values are D[0] to D[N-2].
 */
int D[200005];

/*
 * C contains the cost of food in each town. Note that the array starts from 0,
 * and so the values are C[0] to C[N-1].
 */
int C[200005];

int answer;
int main(void) {
    FILE *input_file;
    FILE *output_file;
    int i;

    /* Open the input and output files. */
    input_file = fopen("backin.txt", "r");
    output_file = fopen("backout.txt", "w");

    /* Read the values of N, K, D, and C from the input file. */
    fscanf(input_file, "%d%d", &N, &K);
    for (i = 0; i < N-1; i++) {
        fscanf(input_file, "%d", &D[i]);
    }
    for (i = 0; i < N; i++) {
        fscanf(input_file, "%d", &C[i]);
    }

    /*
     * TODO: This is where you should compute your solution. Store the minimum
     * total amount that Norman must spend into the variable answer.
     */

    /* Write the answer to the output file. */
    fprintf(output_file, "%d\n", answer);

    /* Finally, close the input/output files. */
    fclose(input_file);
    fclose(output_file);

    return 0;
}