aoj0516.c

#include<stdio.h>
int main(void){
  int i, n, k, sum, max, a[100000];
  while(scanf("%d %d", &n, &k), n){
    sum = max = 0;
    for(i = 0; i < n; i++){
      scanf("%d", &a[i]);
      if(i < k)
        sum+=a[i];
    }
    max = sum;
    for(i = k; i < n; i++){
      sum += a[k] - a[k - i];
      if(sum > max)
	    max = sum;
    }
    printf("%d\n", max);
  }
  return 0;
}