func_code_string: #include <bits/stdc++.h>   using namespace std;   struct node {     int st, ed;   } ch[100010];   bool cmp(node a, node b) { return a.st < b.st; }   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     int n, l, a;     cin >> n >> l >> a;     for (int i = 0; i < n; i++) {       cin >> ch[i].st >> ch[i].ed;       ch[i].ed += ch[i].st;     }     sort(ch, ch + n, cmp);     int num = 0;     num += (ch[0].st) / a;     for (int i = 0; i < n - 1; i++) {       if (ch[i + 1].st - ch[i].ed >= a) {         num += (ch[i + 1].st - ch[i].ed) / a;       }     }     if (ch[n - 1].ed < l) {       num += (l - ch[n - 1].ed) / a;     }     cout << num << endl;     return 0;   }   