#include <iostream>
#include <vector>
#include <queue>
#include <map>
#include <algorithm>
#define ll long long
#define pii pair<ll,ll>
#define ppi pair<pii,ll>
#define fst first
#define snd second
#define pub push_back
using namespace std;
vector<pii> cr,cr2;
vector<ppi> dt;
priority_queue<pii,vector<pii>,greater<pii>> pq;
map<ll,ll> mp;
ll n,a,b,t,crto = 0,rs = 0;
ll gcd(ll x,ll y) {return y?gcd(y,x%y):x;}
int main()
{
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>n>>a>>b;
t = a / gcd(a,b+1);
for (int i=0;i<n;i++)
{
ll l,r;cin>>l>>r;
if (l/b == r/b) {dt.push_back({{l%b,r%b},(l/b)%t});}
else
{
if (r%b != b-1) {dt.push_back({{0,r%b},(r/b)%t});}
if (l%b != 0) {dt.push_back({{l%b,b-1},(l/b)%t});}
if ((l+(b-1))/b <= (r-(b-1))/b)
{
ll l2 = ((l+(b-1))/b)%t;
ll r2 = ((r-(b-1))/b)%t;
if (l2<=r2) {cr.pub({l2,r2});}
else {cr.pub({r2,t-1});cr.pub({0,l2});
}
}
}
}
sort(dt.begin(),dt.end());
sort(cr.begin(),cr.end());
ll l = -1,r = -2;
for (int i=0;i<cr.size();i++)
{
if (r+1<cr[i].fst)
{
if (l!=-1) {cr2.pub({l,r});crto += r - l + 1;}
l = cr[i].fst;
r = cr[i].fst;
}
r = max(r,cr[i].snd);
}
if (l!=-1) {cr2.pub({l,r});crto += r - l + 1;}
cr.clear();
/*
cout<<"-- DT --\n";
for (int i=0;i<dt.size();i++)
{
cout<<dt[i].fst.fst<<" "<<dt[i].fst.snd<<" "<<dt[i].snd<<"\n";
}
cout<<"-- CR2 --\n";
for (int i=0;i<cr2.size();i++)
{
cout<<cr2[i].fst<<" "<<cr2[i].snd<<"\n";
}
*/
ll pv = 0;
for (int i=0;i<dt.size();i++)
{
while (pq.size())
{
if (pq.top().fst < dt[i].fst.fst)
{
rs += crto * (pq.top().fst+1-pv);
pv = pq.top().fst+1;
mp[pq.top().snd]--;
if (mp[pq.top().snd]==0) {crto--;}
pq.pop();
}
else {break;}
}
//cout<<i<<" "<<crto<<" "<<rs<<" "<<pv<<"\n";
auto it = upper_bound(cr2.begin(),cr2.end(),make_pair(dt[i].snd+1,(ll)-1));
if (it != cr2.begin())
{
it = prev(it);
if (dt[i].snd > (it->snd))
{
rs += crto * (dt[i].fst.fst-pv);
pv = dt[i].fst.fst;
mp[dt[i].snd]++;
if (mp[dt[i].snd]==1) {crto++;}
pq.push({dt[i].fst.snd,dt[i].snd});
}
}
else
{
rs += crto * (dt[i].fst.fst-pv);
pv = dt[i].fst.fst;
mp[dt[i].snd]++;
if (mp[dt[i].snd]==1) {crto++;}
pq.push({dt[i].fst.snd,dt[i].snd});
}
//cout<<i<<" "<<crto<<" "<<rs<<" "<<pv<<"\n";
}
while (pq.size())
{
rs += crto * (pq.top().fst+1-pv);
pv = pq.top().fst+1;
mp[pq.top().snd]--;
if (mp[pq.top().snd]==0) {crto--;}
pq.pop();
}
rs += crto * (b - pv);
cout<<rs<<"\n";
return 0;
}
