#include <iostream>
	#include <string>
	#include <math.h>
	#include <set>
	#include <map>
	#include <queue>
	#include <utility>
	#include <algorithm>
	#include <stack>
	#include <bitset>
	#define pb push_back
	using namespace std;
 
	void compile(){
	    #ifndef ONLINE_JUDGE
	    freopen("input.txt", "r", stdin);
	    freopen("output.txt", "w", stdout);
	    #endif
	}

	int main(){
	    compile();
	    int t = 1;
	    //cin >> t;

	    while(t--){
	    	int n, k;
	    	scanf("%d%d",&n,&k);
	    	int a[n];
	    	unsigned long long sum = 0;
	    	for(int i = 0 ; i < n ; i++){
	    		scanf("%d",a+i);
	    		sum += a[i];
	    	}

	    	unsigned long long l = 0, r = 1e15, mid, mx = 0;
	    	while(l <= r){
	    		mid = l + (r - l) / 2;

	    		if(sum * ((mid + 1) * mid) / 2 < k){
	    			l = mid + 1;
	    			mx = max(mx, mid);
	    		}
	    		else if(sum * ((mid + 1) * mid) / 2 > k){
	    			r = mid - 1;
	    		}
	    		else{
	    			cout<<mid * n<<endl;
	    			return 0;
	    		}
	    	}

	    	unsigned long long cnt = 0, mxx = (mx * (mx + 1)) / 2;
	    	sum = 0;
	    	if(mid % 2){
	    		for(int i = n - 1 ; i >= 0 ; i--){
	    			sum += ((unsigned long long)(mx + 1) * a[i]);
	    			if(sum + mxx > k)break;
	    			cnt++;
	    		}
	    	}
	    	else{
	    		for(int i = 0 ; i < n ; i++){
	    			sum += ((unsigned long long)(mx + 1) * a[i]);
	    			if(sum + mxx > k)break;
	    			cnt++;
	    		}
	    	}
	    	unsigned long long ans = cnt + mx;
	    	cout<<ans<<endl;
	    }
	}