// Slower C++ solution:
#include <cstdio>

#include <algorithm>

#include <set>

#define MAX(a,b) ((a)>(b))?(a):(b)

using namespace std;





int main() {

	int n,p,q,r,max=-1,w;

	int i,j;

	int c;

	int *sum;

	set<int> under;

	set<int> over;

	bool flag=false;

	scanf("%d%d",&n,&q);

	sum=(int *)malloc(sizeof(int)*n);

	scanf("%d",&w);

	max=sum[0]=w;

	for(i=1; i<n; ++i) {

		scanf("%d",&w);

		max=MAX(w,max);

		sum[i]=sum[i-1]+w;

	}

	// ?????????w????????§???max????????§?????????p??¨????????????????????§?????????????????????????§??????????

	// ???????????????q??°???q=1?????¨??????????¨????????§£???

	// ?????????????????°??°???c+1??°??¨?????????c=0????????????????????????c=q-2????????£???????????§??????????????£???????????????r??¨?????????

	// ??\???????????????????????¨?????????c=q-2????????£???????????§??????????????£???????????????r??¨??????

	// 1.c<q-2??§?????????????????????????????????????????????????°?????°???????p??§????????? p=(p+max)/2 -> p==(p+max)/2????????????

	// 2.r<=p?????????????????????????????? ???????°?????°???????k??§?????????p=(p+r)/2 -> p==(p+r)/2???????????????

	// 3.r>p????????±????????????????????? ???????°??????§??????k??§?????????p=(p+r)/2

	// 3?????¶???????????£?????????p-(p+r)/2=(p-r)/2??????????????????10??\???????????????????????????????????§??????????????¨???????????§??¢???

	if(q==1) {

		printf("%d\n",sum[n-1]);

		return 0;

	}

	p=max;

	while(1) {

		i=0;

		for(c=0; c<q-1; ++c) {

			for(j=0; i+j<n; ++j) { // j : ?????????????????????

				if(i==0) { // ??????????????????????±??????????????????????????????????

					if(sum[j]>p) { // ?????§?????????????¶???????

//						printf("load over : c=%d, i=%d, j=%d\n",c,i,j); // debug

						i=j;

						j=0;

						break;

					}

				} else { // ?????????????????\??????????????????

					if(sum[i+j]-sum[i-1]>p) { //?????§?????????????¶???????

//						printf("load over : c=%d, i=%d, j=%d\n",c,i,j);  // debug

						i+=j;

						j=0;

						break;

					}

				}

			}

			if(i+j==n-1 && c<q-2) {

				if(p==max || flag) {

//					printf("i=%d, j=%d. finished by less truck\n",i,j);  // debug

					printf("%d\n",p);

					return 0;

				}

				over.insert(p);

				if(flag) {

					++p;

				} else if(!under.empty()) {

					p=((*over.begin())+(*(--under.end())))/2;

				} else {

					p=(max+p)/2;

				}

			}

		}

		r=sum[n-1]-sum[i-1];

		if(r==p) {

//			printf("last truck is full filled.\n");  // debug

			printf("%d\n",p);

			return 0;

		} else if (!flag) {

			if(r<p) {

				over.insert(p);

				if(!under.empty()) {

//					printf("overwrite value p %d to %d ( under not empty )\n",p,((*(over.begin()))+(*(--under.end())))/2);  // debug

					p=((*(over.begin()))+(*(--under.end())))/2;

				} else {

//					printf("overwrite value p %d to %d ( under empty )\n",p,r+(p-r)/2);  // debug

					p=r+(p-r)/2;

				}

			} else if(r>p) {

				if((!over.empty() && !under.empty() && (*(over.begin()))-(*(--under.end()))<=10) || r-p<=10 ) {

					flag=true;

					under.insert(p);

//					printf("overwrite value p %d to %d ( inclemental overwrite )\n",p,p+1);  // debug

					++p;

				} else {

					under.insert(p);

					if(!over.empty()) {

//						printf("overwrite value p %d to %d ( over not empty )\n",p,((*(over.begin()))+(*(--under.end())))/2);  // debug

						p=((*(over.begin()))+(*(--under.end())))/2;

					} else {

//						printf("overwrite value p %d to %d ( over empty )\n",p,p+(r-p)/2);  // debug

						p=p+(r-p)/2;

					}

				}

			}

		} else {

			if(r>p) {

//				printf("overwrite value p %d to %d ( inclement overwrite second onward turn )\n",p,p+1);  // debug

				++p;

			} else {

//				printf("inclement search finished.\n");  // debug

				printf("%d\n",p);

				return 0;

			}

		}

	}

	return 0;

}

// Faster C++ solution for the same problem (measured speedup: 4.832342155126724x):
#include <cstdio>

#include <algorithm>

#define MAX(a,b) ((a)>(b))?(a):(b)

#define MIN(a,b) ((a)<(b))?(a):(b)

using namespace std;





int main() {

	int n,p,q,r,max=-1,w;

	int i,j;

	int c;

	int *sum;

	int p_under;

	int p_over;

	bool flag=false;

	scanf("%d%d",&n,&q);

	sum=(int *)malloc(sizeof(int)*n);

	scanf("%d",&w);

	max=sum[0]=w;

	for(i=1; i<n; ++i) {

		scanf("%d",&w);

		max=MAX(w,max);

		sum[i]=sum[i-1]+w;

	}

	if(q==1) {

		printf("%d\n",sum[n-1]);

		return 0;

	}

	p=max;

	p_over=sum[n-1];

	p_under=0;

	while(1) {

		i=0;

		for(c=0; c<q-1; ++c) {

			for(j=0; i+j<n; ++j) {

				if(i==0) {

					if(sum[j]>p) {

						i=j;

						j=0;

						break;

					}

				} else {

					if(sum[i+j]-sum[i-1]>p) {

						i+=j;

						j=0;

						break;

					}

				}

			}

			if(i+j==n-1 && c<q-2) {

				if(p==max || flag) {

					printf("%d\n",p);

					return 0;

				}

				p_over=MIN(p_over,p);

				if(flag) {

					++p;

				} else {

					p=(p_under+p_over)/2;

				}

			}

		}

		r=sum[n-1]-sum[i-1];

		if(r==p) {

			printf("%d\n",p);

			return 0;

		} else if (!flag) {

			if(r<p) {

				p_over=MIN(p_over,p);

				p=(p_over+p_under)/2;

			} else if(r>p) {

				if(p_over-p_under<=10 || r-p<=10 ) {

					flag=true;

					p_under=MAX(p_under,p);

					++p;

				} else {

					p_under=MAX(p_under,p);

					p=(p_under+p_over)/2;

				}

			}

		} else {

			if(r>p) {

				++p;

			} else {

				printf("%d\n",p);

				return 0;

			}

		}

	}

	return 0;

}