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

被hack了，求条