# include<bits/stdc++.h>
using namespace std;
const int N = 10e5 + 5;
long long m[N], n, x, ans;
int main(){
	cin >> n >> x;
	for(int i = 1; i <= n; i++){
		cin >> m[i];
		if(i >= 2) while(m[i] + m[i - 1] > x) m[i]--, ans++;
	}
	cout << ans;
	return 0;
}