#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define pa pair<ll, ll>
#define fi first
#define se second
#define bit(mask, j) ((mask >> j) & 1)
const ll mod = 1e9 + 7;
const ll INF = 1e18;
//--------------------------------------------------------------------
ll n, A, B;
struct Node {
ll l = -1;
ll r = -1;
ll cur = 0;
ll lazy = 0;
};
vector<Node> tree;
ll ID = 0;
void add(ll id, ll len, ll val) {
tree[id].cur = len;
tree[id].lazy = 1;
}
void down(ll id, ll l, ll r) {
if(tree[id].l == -1) {
tree[id].l = ++ID;
tree.push_back(Node());
}
if(tree[id].r == -1) {
tree[id].r = ++ID;
tree.push_back(Node());
}
ll mid = l + r >> 1;
if(tree[id].lazy == 0) return;
add(tree[id].l, mid - l + 1, 1);
add(tree[id].r, r - mid, 1);
tree[id].lazy = 0;
}
void merge(Node &mid, Node &L, Node &R) {
mid.cur = L.cur + R.cur;
}
void update(ll u, ll v, ll id, ll l, ll r) {
if(u > r || v < l) return;
if(u <= l && v >= r) {
add(id, r - l + 1, 1);
return;
}
down(id, l, r);
ll mid = l + r >> 1;
ll idl = tree[id].l, idr = tree[id].r;
update(u, v, idl, l, mid);
update(u, v, idr, mid + 1, r);
merge(tree[id], tree[idl], tree[idr]);
}
ll get(ll u, ll v, ll id, ll l, ll r) {
if(u > r || v < l) return 0;
if(u <= l && v >= r) return tree[id].cur;
down(id, l, r);
ll mid = l + r >> 1;
ll idl = tree[id].l, idr = tree[id].r;
return get(u, v, idl, l, mid) + get(u, v, idr, mid + 1, r);
}
void hbmt() {
cin >> n >> A >> B;
ll cnt = 0;
// if(n == 1) {
// ll l, r;
// cin >> l >> r;
// ll bcnn = A*B / __gcd(A, B);
// }
tree.push_back(Node());
ll res = A * (B + 1) / __gcd(A, B + 1);
res = res / (B + 1) * B;
FOR(i, 1, n) {
ll l, r;
cin >> l >> r;
ll x = l % res, y = r % res;
// cout << x << ' ' << y << ' ' << res << '\n';
if(r - l + 1 >= res) {
cout << res;
return;
}
if(x <= y) {
update(x, y, 0, 0, res - 1);
}
else {
update(0, y, 0, 0, res - 1);
update(x, res - 1, 0, 0, res - 1);
}
}
cout << tree[0].cur;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
#define NAME "hbmt"
if(fopen(NAME".inp", "r")) {
freopen(NAME".inp", "r", stdin);
freopen(NAME".out", "w", stdout);
}
//int t;cin>>t;while(t--)
hbmt();
return 0;
}
