#include <bits/stdc++.h>
#include <string>
#include <vector>
#include <algorithm>
#include <math.h>
#include <iostream>
#include <numeric>
#define rep(i,n) for (int i = 0;i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define chmax(x,y) x = max(x,y)
int INF = 1e9;


int main(){
	int n;
	ll x;cin >> n >> x;
	vector<ll> a(n);
	rep(i,n) cin >> a[i];
	ll ans = 0;
	if(a[0]>x) {
		ans += a[0]-x;
		a[0] = x;
	}
	rep(i,n-1){
		//cout << " " << ans << endl;
		if(a[i]+a[i+1]>x){
			ans += a[i+1] - (x-a[i]);
			a[i+1] = x-a[i];
		}
	}
	//rep(i,n) cout << a[i] << endl;
	cout << ans << endl;
} 


#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <cstdio>
#include <cmath>
#include <tuple>
#include <iomanip>
#include <numeric>
#include <unordered_map>
#include <sstream>
#include<limits.h>
#include<float.h>
#include<list>
#include <array>
#include <complex>
#include<stdio.h>
#include<string.h>
#include <bitset>
// #include<assert.h>
#include<random>
using namespace std;
#define int long long

#define I32_MAX 2147483647
#define I64_MAX 9223372036854775807LL
#define I64_MAX2 1223372036854775807LL
#define INF I64_MAX2
#define MOD 1000000007
// #define MOD 998244353 
#define MEM_SIZE 10000
#define DEBUG_OUT true
#define ALL(x) (x).begin(), (x).end()

template<typename T> void DEBUG(T e){if(DEBUG_OUT == false)return; std::cout << e <<" ";}
template<typename T> void DEBUG(const std::vector<T>& v){if(DEBUG_OUT == false)return;for(const auto& e : v){std::cout<< e << " "; } std::cout << std::endl;}
template<typename T> void DEBUG(const std::vector<std::vector<T> >& vv){if(DEBUG_OUT == false)return;for(const auto& v : vv){ DEBUG(v); } }
template<class T,class... Ts> void DEBUG(T d, Ts... e){if(DEBUG_OUT == false)return;DEBUG(d);DEBUG(e...);}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; abort();}}
template< typename T1, typename T2 > inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template< typename T1, typename T2 > inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

void solve(void)
{ 
  int N; cin>>N;
  vector<int> vec (N,0);
  for (int i = 0; i < N; i++)
  {
     cin>>vec[i];
  }
  vector<int> data;
  data.push_back(-1*vec[0]);
  for (int i = 1; i < N; i++)
  {
    int X = -1*vec[i];
    auto itr = upper_bound(ALL(data),X);
    if(itr == data.end())
    {
      data.push_back(X);
    }
    else
    {
      *itr =X;
    }

  }
  cout<<data.size()<<endl;
  
  return;
}
int32_t main(int32_t argc, const char *argv[])
{
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  std::cout << std::fixed;
  std::cout << std::setprecision(11);
  solve();

  return 0;
}
