#include<bits/stdc++.h> using namespace std; typedef long long ll; const int maxn = 4e6; int n, m, tot, sum[maxn + 3]; ll A, B, C, l, r, temp[maxn + 3]; pair<ll, ll> sect[maxn + 3]; ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; } int main() { scanf("%d %lld %lld", &n, &A, &B); C = A / gcd(A, B + 1) * B; for (int i = 1; i <= n; i++) { scanf("%lld %lld", &l, &r); if (r - l + 1 >= C) { printf("%lld\n", C); return 0; } l %= C, r %= C; if (l <= r) { sect[++tot] = make_pair(l, r); } else { sect[++tot] = make_pair(0, r); sect[++tot] = make_pair(l, C - 1); } } for (int i = 1; i <= tot; i++) { temp[++m] = sect[i].first; temp[++m] = sect[i].second + 1; } sort(temp + 1, temp + m + 1); for (int i = 1; i <= tot; i++) { int x = lower_bound(temp + 1, temp + m + 1, sect[i].first) - temp; int y = lower_bound(temp + 1, temp + m + 1, sect[i].second + 1) - temp; sum[x]++, sum[y]--; } ll ans = 0; for (int i = 1; i <= m; i++) { sum[i] += sum[i - 1]; if (sum[i]) { ans += temp[i + 1] - temp[i]; } } printf("%lld\n", ans); return 0; }

strange_device.cpp: In function 'int main()':
strange_device.cpp:12:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   12 |  scanf("%d %lld %lld", &n, &A, &B);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:15:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   15 |   scanf("%lld %lld", &l, &r);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~