#include<iostream>
using namespace std;
int m,n;
int a[10111]; 
int b[10111];
int sum;
int main()
{
	cin >> n >> m;
	for(int i = 1;i <= n;i++){
		cin >> a[i];
	}
	for(int i = 1;i <= m;i++){
		b[i] = a[i];
	}
	int i = m;
	while(true){
		for(int j = 1;j <= m;j++){
			b[j]--;
			if(b[j] == 0){
				i++;
				b[j] = a[i];	
			}
		}
		int r = 1;
		sum++;
		for(int j = 1;j <= m;j++){
			if(b[j] > 0){
				r = 0;
			}
		}
		if(r == 1){
			cout << sum;
			return 0;
		}
	}
	return 0;
}

#2wa,求助