#include <bits/stdc++.h>   using namespace std;   const int N = (int)3e5 + 7;   int n, k;   int x[N], y[N];   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cin >> n >> k;     for (int i = 1; i <= n; i++) {       cin >> x[i];     }     for (int i = 1; i <= n; i++) {       cin >> y[i];     }     long long f, s;     f = s = 0;     for (int i = 1; i <= n; i++) {       f = max(0LL, x[i] + f - y[i] * 1LL * k);       s = max(0LL, y[i] + s - x[i] * 1LL * k);       if (f > k || s > k) {         puts( NO );         return 0;       }     }     puts( YES );   }   