func_code_string: #include <bits/stdc++.h>   int main() {     int n;     int x;     int sum = 0;     std::cin >> n;     std::cin >> x;     unsigned int t1 = 0, t2 = 0, tcurr = 1;     for (int i = 0; i < n; i++) {       std::cin >> t1;       std::cin >> t2;       sum += (t1 - tcurr) % x + t2 - t1 + 1;       tcurr = t2 + 1;     }     std::cout << sum;     return 0;   }   