#include<bits/stdc++.h>
using namespace std;
#define f first
#define s second
typedef long long ll;
const int maxn = 2e6+5;
int n, sz;
ll a, b;
pair<ll, ll> A[maxn];
vector<pair<int, int>> qq[maxn];
map<ll, int> mp;
vector<pair<ll, ll>> rng, vec;
vector<ll> pos;
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> a >> b;
ll cyc = a/__gcd(a, b+1);
for(int i = 0; i < n; i++){
cin >> A[i].f >> A[i].s;
ll lb = A[i].f/b+1, rb = A[i].s/b-1;
if(rb >= lb){
if(rb - lb+1 >= cyc)rng.push_back({0, cyc-1});
else{
ll lm = lb%cyc, rm = rb%cyc;
if(lm <= rm)vec.push_back({lm, rm});
else{
vec.push_back({lm, cyc-1});
vec.push_back({0, rm});
}
}
}
pos.push_back(A[i].f%b);
pos.push_back(A[i].s%b + 1);
}
pos.push_back(-1);
pos.push_back(0);
pos.push_back(b);
sort(pos.begin(), pos.end());
pos.erase(unique(pos.begin(), pos.end()), pos.end());
sort(vec.begin(), vec.end());
for(auto v: vec){
if(rng.empty() || rng.back().s < v.f-1)rng.push_back(v);
else rng.back().s = max(rng.back().s, v.s);
}
sz = pos.size()-1;
for(int i = 0; i < n; i++){
ll lb = A[i].f/b, rb = A[i].s/b;
if(lb == rb){
int pp = lower_bound(rng.begin(), rng.end(), make_pair(lb%cyc, cyc+1))-rng.begin()-1;
if(pp < 0 || rng[pp].s < lb%cyc){
int ql = lower_bound(pos.begin(), pos.end(), A[i].f%b)-pos.begin(), qr = upper_bound(pos.begin(), pos.end(), A[i].s%b) - pos.begin();
qq[ql].push_back({lb%cyc, 0});
qq[qr].push_back({lb%cyc, 1});
}
}
else{
int pp = lower_bound(rng.begin(), rng.end(), make_pair(lb%cyc, cyc+1))-rng.begin()-1;
if(pp < 0 || rng[pp].s < lb%cyc){
int ql = lower_bound(pos.begin(), pos.end(), A[i].f%b)-pos.begin();
qq[ql].push_back({lb%cyc, 0});
}
pp = lower_bound(rng.begin(), rng.end(), make_pair(rb%cyc, cyc+1))-rng.begin()-1;
if(pp < 0 || rng[pp].s < rb%cyc){
int qr = upper_bound(pos.begin(), pos.end(), A[i].s%b) - pos.begin();
qq[1].push_back({rb%cyc, 0});
qq[qr].push_back({rb%cyc, 1});
}
}
}
int crr = 0;
ll ans = 0;
for(int i = 1; i < sz; i++){
for(auto v: qq[i]){
if(v.s){
mp[v.f]--;
if(!mp[v.f])crr--;
}
else{
if(!mp[v.f])crr++;
mp[v.f]++;
}
}
ans += (pos[i+1]-pos[i])*crr;
}
for(auto v: rng){
ans+=b*(v.s-v.f+1);
}
cout << ans;
}
