RT

#include<bits/stdc++.h>
using namespace std;

int main()
{
	unsigned long long int n,x,cnt=0;
	unsigned long long int a[100005];
	cin>>n>>x;
	cin>>a[1]>>a[2];
	for(int i=3;i<=n;i++){
		cin>>a[i];
		int t1=a[i-2]+a[i-1]-x,t2=a[i-1]+a[i]-x;
		if(t1<=0) continue;
		a[i-1]-=t1;
		cnt+=t1;
	}
	int t1=a[n-2]+a[n-1]-x,t2=a[n-1]+a[n]-x;
	if(t1>0||t2>0){
		a[n-1]-=max(t1,t2);
		cnt+=max(t1,t2);
	}
	
	cout<<cnt;
	return 0;
}

话说unaccepted 100分是什么鬼