#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#define int ll
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
#define INF INT_MAX
#define MOD 1000000007
#define all(x) x.begin(), x.end()
namespace DST {
struct node {
int sum{}, lazy{}, tot{};
unique_ptr<node> l, r;
};
auto root = make_unique<node>();
void upd(unique_ptr<node> &n, int l, int r){
if(!n) return;
if(n->sum) n->tot = r-l+1;
else{
n->tot = 0;
if(n->l) n->tot += n->l->tot;
if(n->r) n->tot += n->r->tot;
}
return;
}
void update(unique_ptr<node> &n, int l, int r, int L, int R, int val){
if(r < L or R < l) return;
if(L <= l and r <= R){
n->sum += val;
upd(n, l, r);
return;
}
if(!n->l) n->l = make_unique<node>();
if(!n->r) n->r = make_unique<node>();
int m = (l+r)/2;
update(n->l, l, m, L, R, val);
update(n->r, m+1, r, L, R, val);
upd(n, l, r);
}
void update(int L, int R, int val){
update(root, 0, 1e18+10, L, R, val);
}
int query(){
return root->tot;
}
};
struct rect {
int x1, y1, x2, y2;
};
int rect_solve(vector<rect> &B){
ll ans = 0;
vector<array<int, 4>> q;
for(auto i : B){
q.push_back({i.x2+1, -1, i.y1, i.y2+1});
q.push_back({i.x1, 1, i.y1, i.y2+1});
}
sort(all(q)); int prev_x = 0;
for(auto [x, offset, y1, y2] : q){
ans += ll(x-prev_x)*DST::query();
prev_x = x;
DST::update(y1, y2-1, offset);
}
return ans;
}
int up(int a, int b){return (a+b-1)/b;}
int down(int a, int b){return a/b;}
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
int Q, A, B; cin >> Q >> A >> B;
vector<rect> RC; int A1 = A/__gcd(A, B+1);
while(Q--){
int l, r; cin >> l >> r;
int k1 = up(l, B), k2 = down(r, B);
auto ins = [&](int x1, int x2, int y1, int y2){
if(x2-x1+1 >= A1) RC.push_back({0, y1, A1-1, y2});
else{
int t1 = x1%A1, t2 = x2%A1;
if(t1 <= t2) RC.push_back({t1, y1, t2, y2});
else RC.push_back({t1, y1, A1-1, y2}), RC.push_back({0, y1, t2, y2});
}
};
if(k1 <= k2){
if(k1 < k2) ins(k1, k2-1, 0, B-1);
if(l%B != 0) ins(k1-1, k1-1, l%B, B-1);
ins(k2, k2, 0, r%B);
}else{
ins(k2, k2, l%B, r%B);
}
}
cout << rect_solve(RC) << endl;
return 0;
}
