//https://www.instagram.com/_modwwe/
#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2")
#include<bits/stdc++.h>
#define int long long
//#define ll long long
#define down cout<<'\n';
#define NHP ios_base::sync_with_stdio(0);cout.tie(0);cin.tie(0);
#define modwwe int t;cin>>t; while(t--)
#define bit(i,j) (i>>j&1)
#define sobit(a) __builtin_popcountll(a)
#define task "test"
#define fin(x) freopen(x".inp","r",stdin)
#define fou(x) freopen(x".out","w",stdout)
#define pb push_back
#define checktime cerr << (double)clock() / CLOCKS_PER_SEC * 1000 << " ms";
using namespace std;
void phongbeo();
const int inf=1e18;
const int mod2=1e9+7;
const int mod1=998244353;
struct icd
{
int a,b;
};
struct ib
{
int a;
int b;
};
struct ic
{
int a,b,c;
};
struct id
{
int a,b,c,d;
};
struct ie
{
int a,b,c, d,e,f;
};
int n,m,s1,s2,s4,s3,sf,k,r,mid,s5,s6,mx,s7,s8,s9,mx2,res,dem2=0,dem=0,l;
int i,s10,s12;
int el=29;
main()
{
#ifndef ONLINE_JUDGE
/// fin(task),fou(task);
#endif
NHP
/// cin>>s1;
// modwwe
phongbeo(),down
}
vector<ib> v;
ib a[1000001];
bool cmp(ib a,ib b)
{
return a.a<b.a;
}
void phongbeo()
{
cin>>n>>l>>r;
for(int i=1; i<=n; i++)
cin>>a[i].a>>a[i].b,s2=max(s2,a[i].b);
s3=l/__gcd(l,r+1);
s5=s2/r;
if(s3>s5)
{
for(int i=1; i<=n; i++)
v.pb({a[i].a,a[i].b});
}
else
{
s3=r*s3;
for(int i=1; i<=n; i++)
{
if(a[i].a/s3!=a[i].b/s3)
v.pb({a[i].a%s3,s3-1}),
v.pb({0,a[i].b%s3});
else
{
v.pb({a[i].a%s3,a[i].b%s3});
}
}
}
s2=-1;
s3=0;
sort(v.begin(),v.end(),cmp);
for(int i=0; i<v.size(); i++)
{
//cout<<v[i].a-1<<" "<<v[i].b<<" "<<s2,down
s2=max(v[i].a-1,s2);
s3+=max(0ll,v[i].b-s2);
s2=max(s2,v[i].b);
}
cout<<s3;
}
