#include <stdio.h>

int memo[53][53];

int cut(int* v, int esq, int dir){
    if(memo[esq][dir]!=-1)
        return memo[esq][dir];

    if(esq+1 == dir){
        memo[esq][dir] = 0;
        return 0;
    } else {
        int tamTronco = v[dir] - v[esq];
        int min = cut(v, esq, esq+1) + cut(v, esq+1, dir) + tamTronco;

        for(int i=esq+2; i<dir; i++){
            int aux = cut(v, esq, i) + cut(v, i, dir) + tamTronco;
            if(aux<min){
                min = aux;
            }
        }
        memo[esq][dir] = min;
        return min;
    }
}

int main(){
    int tam, nCortes, v[53];

    while(true){
        scanf("%d", &tam);
        if(tam != 0){
            scanf("%d", &nCortes);
            v[0] = 0;
            for(int i=1; i<=nCortes; i++){
                scanf("%d", &v[i]);
            }

            v[nCortes+1] = tam;
            for(int i=0; i<=nCortes+1; i++)
                for(int j=0; j<=nCortes+1; j++)
                    memo[i][j] = -1;

            int out = cut(v, 0, nCortes+1);
            printf("The minimum cutting is %d.\n", out);

        } else {
            break;
        }
    }

    return 0;
}