#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
#define yes cout << "Yes" << "\n"
#define no cout << "No" << "\n"
#define pb push_back
#define F first
#define S second
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef pair <int, int> pii;
typedef vector <pii> vii;
typedef vector <ll> vi;
template<typename T>
void read(vector<T>& v) {
for (auto &x : v) cin >> x;
}
template<typename T>
void print(const vector<T>& v) {
for (auto &x : v) cout << x << ' ';
cout << "\n";
}
const ll MAX = 1e6 + 5;
const ll MOD = 1e9 + 7;
vi b(MAX);
vi c(MAX);
void solve() {
int n, k;
cin >> n >> k;
vi a(n);
read(a);
for (int i = 0; i < n - 1; i++) {
int b, c;
cin >> b >> c;
}
int cem = 0;
int say = 0;
for (auto x : a) {
if (cem + x > k) {
say++;
cem = 0;
}
cem += x;
}
cout << say << '\n';
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
//cin >> t;
for (int i = 1; i <= t; i++) {
solve();
}
}
