#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef long long ll;
typedef double db;
typedef vector<long long> vl;
typedef pair<long long , long long > pl;
const int N=1e6+1;
#define po pop_back
#define pb push_back
#define mk make_pair
#define lw lower_bound
#define up upper_bound
#define ff first
#define ss second
#define boost ios_base::sync_with_stdio(); cin.tie(0); cout.tie(0);
#define MOD 1000000007
#define MAX 1e18
#define MIN -1e18
#define rep(i,a,b) for(ll i=a;i<=b;i++)
#define per(i,a,b) for(ll i=b;i>=a;i--)
#define con continue
#define freopen freopen("input.txt", "r", stdin);freopen("output.txt", "w", stdout);
#define PI 3.14159265358979323846264338327950288419716939937510582097494459230781640628
// typedef tree<ll , null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
// template< typename T>
// using indexed_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
ll n,m,ans,mid,mn,mx,cnt,T,sum,h1,h2,e[1234567],b[1234567],c[1234567],d[1<<20],k,i,j,l,x,y,r,z,h,a[1234567],w,c1[1234][1234];
bool used[1234567],used1[1234567];
pl p[1234567];
string s,s1[1234567];
map<ll,ll> mp;
map<pl,ll> mpl;
vl vec,vec1,ansvec;
vector<ll> v[1234567],v1[1234567];
vector<ll> vp[1234567];
set<pl> st;
int main(){
ll A,B;
cin>>n>>A>>B;
while(n--){
cin>>l>>r;
for(ll i=l;i<=r;i++){
x = (i+(i/B))%A;
y = i%B;
st.insert({x,y});
}
}
cout<<st.size();
}
