#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <queue>
#include <stack>
#include <bitset>
#include <math.h>
#include <fstream>
#include <iomanip>
using namespace std;
using ll = long long;
using ld = long double;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vvvvll = vector<vvvll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
using vld = vector<ld>;
using vvld = vector<vld>;
using vstr = vector<string>;
using pll = pair<ll, ll>;
using vpll = vector<pll>;
using vvpll = vector<vpll>;
using pb = pair<bool, bool>;
using vpb = vector<pb>;
using vvpb = vector<vpb>;
using vi = vector<int>;
using vvi = vector<vi>;
const ll mod = (ll)1e9 + 7;
const ll inf = (ll)1e18;
#define FAST ios_base::sync_with_stdio(0)
#define FASTIN cin.tie(0)
#define FASTOUT cout.tie(0)
#define upmin(a, b) a = min(a, b)
#define upmax(a, b) a = max(a, b)
#define pr(x) cout << x << endl;
#define prv(v) cout << #v << ": "; for(auto it = v.begin(); it != v.end(); ++it) cout << *it << " "; cout << endl;
#define prvv(v) for(auto it : v) { for(auto it2 : it) cout << it2 << " "; cout << endl; } cout << endl;
#define wpr(x) cout << #x << " = " << (x) << endl;
#define wprv(v) cout << #v << ": " << endl; for(auto it : v) cout << *it << " "; cout << endl;
#define wprvv(v) cout << #v << ": " << endl; for(auto it : v) { for(auto it2 : it) cout << it2 << " "; cout << endl; } cout << endl;
#define rep(i,s,e) for(ll i = s; i < e; i++)
#define all(x) x.begin(),x.end()
#define pb push_back
ll n, A, B;
ll x(ll t)
{
return (t + t / B) % A;
}
ll y(ll t)
{
return t % B;
}
void solve()
{
cin >> n >> A >> B;
set<pll> s;
rep(i, 0, n) {
ll l, r;
cin >> l >> r;
for (ll t = l; t <= r; t++) {
s.insert({ x(t), y(t) });
}
}
ll res = s.size();
pr(res);
}
int main()
{
FAST;
FASTIN; FASTOUT;
solve();
}
