#include<bits/stdc++.h>
#define int long long
using namespace std;
int read()
{
	int x = 0, f = 1;
	char c = getchar();
	while(c != EOF and !isdigit(c))
	{
		if(c == '-')f = -1;
		c = getchar();
	}
	while(isdigit(c))
	{
		x = x * 10 + c - '0';
		c = getchar();
	}
	return x * f;
}
int n, k, a[1000010], f[1000010];
signed main()
{
	int T = 1;
	while(T --)
	{
		n = read();
		k = read();
		for(int i = 0;i <= 3 * n;i ++)f[i] = 0x3f3f3f3f3f3f3f3f;
		f[0] = 0;
		for(int i = 0;i< n;i ++)a[i] = a[i + n] = read();
		for(int i = 0;i < 2*n;i ++)
		{
			for(int j = 0;a[i]+i+j < 2*n;j ++)
			{
				//if(f[j] < f[i] + (j - i - a[i] + 1))break;
				f[a[i]+i+j] = min(f[a[i]+i+j], f[i] + j+1);
			}
			//cout<<f[i]<<endl;
		}
		cout<<min(f[k], f[k+n])<<'\n';
		
	}
	return 0;
}