#include <bits/stdc++.h>
using namespace std;
int i, j, k, n, m, t, l[55], r[55], cnt;
int g[100500], f[100500][55], pre[100500][55];
int su(int a, int b) {
  a += b;
  return (a >= 998244353) ? a - 998244353 : a;
}
void get(int x) {
  int i, j, k, res = 0, l1, r1;
  for (i = x; i <= m; i += x) {
    memset(f[i], 0, sizeof(f[i]));
    memset(pre[i], 0, sizeof(pre[i]));
  }
  for (i = 1; i <= n; i++) {
    r1 = (r[i] / x) * x;
    l1 = ((l[i] + x - 1) / x) * x;
    if (l1 > r1) {
      return;
    }
    if (i == 1) {
      for (j = l1; j <= r1; j += x) {
        f[j][i] = 1;
      }
    } else {
      for (j = x; j <= m; j += x) {
        cnt++;
        if (j <= l1) {
          continue;
        }
        if (j <= r1 + x) {
          f[j][i] = pre[j - l1][i - 1];
        } else {
          f[j][i] = su(pre[j - l1][i - 1], 998244353 - pre[j - r1 - x][i - 1]);
        }
      }
    }
    for (j = x; j <= m; j += x) {
      pre[j][i] = su(pre[j - x][i], f[j][i]);
    }
  }
  for (i = x; i <= m; i += x) {
    res = su(res, f[i][n]);
  }
  g[x] = res;
}
int main() {
  scanf("%d%d", &n, &m);
  for (i = 1; i <= n; i++) {
    scanf("%d%d", &l[i], &r[i]);
  }
  for (i = 1; i <= m; i++) {
    get(i);
  }
  for (i = m; i >= 1; i--) {
    for (j = i + i; j <= m; j += i) {
      g[i] = su(g[i], 998244353 - g[j]);
    }
  }
  printf("%d", g[1]);
}
