#include "bits/stdc++.h"
using namespace std;
#define ar array
#define i128 __int128
#define int long long
int bp(int a, int b, int mod){
int r = 1;
while(b){
if(b&1){
r = (i128)r * (i128)a % mod;
} a = (i128)a * (i128)a % mod, b >>= 1;
} return r;
}
/*
3 5 12
0 23
60 60
81 83
*/
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
int n, A, B; cin>>n>>A>>B;
vector<ar<int, 2>> s(n);
for(int i=0;i<n;i++){
cin>>s[i][0]>>s[i][1];
}
int D = B + 1;
int G = __gcd(A, D);
vector<ar<int, 3>> ss;
vector<ar<int, 2>> a;
for(int i=0;i<n;i++){
int l = s[i][0], r = s[i][1];
int bl = l / B, br = r / B;
if(bl == br){
ss.push_back({l % B, r % B, (bl*D) % A / G});
} else {
ss.push_back({l % B, B - 1, (bl*D) % A / G});
ss.push_back({0, r % B, (br*D) % A / G});
int c = (br - bl - 1);
if(c){
a.push_back({((bl+1)*D) % A / G, c});
}
}
}
A /= G, D /= G;
int res = 0;
//~ if(A == 1 && !a.empty()){
//~ cout<<B<<"\n";
//~ return 0;
//~ }
vector<ar<int, 2>> tot;
i128 inv = 0;
if(!a.empty()){
if(A > 1) inv = bp(D, A - 2, A);
for(auto& x : a){
x[0] = (i128)x[0] * inv % A;
if(x[1] >= A){
cout<<A * B<<"\n";
return 0;
}
x[1] = (x[0] + x[1] - 1) % A;
if(x[0] <= x[1]) tot.push_back({x[0], x[1]});
else {
tot.push_back({x[0], A - 1});
tot.push_back({0, x[1]});
}
}
sort(tot.begin(), tot.end());
int r = -1;
for(auto& x : tot){
if(r < x[0]){
res += (x[1] - x[0] + 1) * B;
r = x[1];
} else if(r < x[1]){
res += (x[1] - r) * B;
r = x[1];
} x[1] = r;
}
}
sort(ss.begin(), ss.end());
map<int, int> mm;
for(auto& x : ss){
if(!a.empty()){
int p = (i128)x[2] * inv % A;
auto it = lower_bound(tot.begin(), tot.end(), (ar<int, 2>){p + 1, -1});
if(it != tot.begin()){
it--;
if(p <= (*it)[1]) continue;
}
}
if(!mm.count(x[2]) || mm[x[2]] < x[0]) res += (x[1] - x[0] + 1), mm[x[2]] = x[1];
else if(mm[x[2]] < x[1]) res += (x[1] - mm[x[2]]), mm[x[2]] = x[1];
}
cout<<res<<"\n";
}
