#include <stdio.h>
#define N 1000000
unsigned int X = 12345;
int rand_() {
return (X *= 3) >> 1;
}
long long gcd(long long a, long long b) {
return b == 0 ? a : gcd(b, a % b);
}
long long xx[N * 2], yy[N * 4], ll_[N * 2], rr_[N * 2];
int compare_x(int i, int j) {
return xx[i] == xx[j] ? 0 : (xx[i] < xx[j] ? -1 : 1);
}
int compare_y(int i, int j) {
return yy[i] == yy[j] ? 0 : (yy[i] < yy[j] ? -1 : 1);
}
int compare_l(int i, int j) {
return ll_[i] == ll_[j] ? 0 : (ll_[i] < ll_[j] ? -1 : 1);
}
int (*compare)(int, int);
void sort(int *ii, int l, int r) {
while (l < r) {
int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;
while (j < k) {
int c = compare(ii[j], i_);
if (c == 0)
j++;
else if (c < 0) {
tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
i++, j++;
} else {
k--;
tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
}
}
sort(ii, l, i);
l = k;
}
}
int main() {
static long long ll[N], rr[N];
static int ii_[N * 4], ii1[N * 2], kk[N * 2];
int n, n_, n1, i, j, x, cnt;
long long a, b, l, r, ans;
scanf("%d%lld%lld", &n, &a, &b), a /= gcd(a, b + 1);
for (i = 0; i < n; i++)
scanf("%lld%lld", &ll[i], &rr[i]);
n_ = 0, n1 = 0;
for (i = 0; i < n; i++) {
l = ll[i] / b, r = rr[i] / b;
if (l == r)
xx[n_] = l % a, yy[n_ << 1 | 0] = ll[i] % b, yy[n_ << 1 | 1] = rr[i] % b + 1, n_++;
else {
xx[n_] = l % a, yy[n_ << 1 | 0] = ll[i] % b, yy[n_ << 1 | 1] = b, n_++;
xx[n_] = r % a, yy[n_ << 1 | 0] = 0, yy[n_ << 1 | 1] = rr[i] % b + 1, n_++;
if (r - l > 1) {
l++, r--;
if (r - l + 1 >= a) {
printf("%lld\n", a * b);
return 0;
}
l %= a, r %= a;
if (l <= r)
ll_[n1] = l, rr_[n1] = r, n1++;
else {
ll_[n1] = l, rr_[n1] = a - 1, n1++;
ll_[n1] = 0, rr_[n1] = r, n1++;
}
}
}
}
for (i = 0; i < n_; i++)
ii_[i] = i;
compare = compare_x, sort(ii_, 0, n_);
for (i = 0; i < n1; i++)
ii1[i] = i;
compare = compare_l, sort(ii1, 0, n1);
ans = 0;
for (i = 0, j = 0, r = -1, x = 0; i < n_; i++) {
while (j < n1 && ll_[ii1[j]] <= xx[ii_[i]]) {
int i1 = ii1[j++];
if (r < ll_[i1])
ans += rr_[i1] - ll_[i1] + 1, r = rr_[i1];
else if (r < rr_[i1])
ans += rr_[i1] - r, r = rr_[i1];
}
xx[ii_[i]] = r >= xx[ii_[i]] ? -1 : (i + 1 == n_ || xx[ii_[i + 1]] != xx[ii_[i]] ? x++ : x);
}
ans *= b;
for (i = 0; i < n_ * 2; i++)
ii_[i] = i;
compare = compare_y, sort(ii_, 0, n_ * 2);
cnt = 0;
for (i = 0; i + 1 < n_ * 2; i++) {
int i_ = ii_[i];
x = xx[i_ >> 1];
if ((i_ & 1) == 0) {
if (x != -1 && kk[x]++ == 0)
cnt++;
} else {
if (x != -1 && --kk[x] == 0)
cnt--;
}
ans += (yy[ii_[i + 1]] - yy[ii_[i]]) * cnt;
}
printf("%lld\n", ans);
return 0;
}
