#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3f;
const long long mod = 998244353;
inline int read() {
  int x = 0, f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + ch - 48;
    ch = getchar();
  }
  return x * f;
}
int mu[100007], ck[100007], prime[100007], tot;
inline void init() {
  mu[1] = 1;
  for (int i = 2; i < 100007; i++) {
    if (!ck[i]) prime[++tot] = i, mu[i] = -1;
    for (int j = 1; j <= tot && i * prime[j] < 100007; j++) {
      int now = i * prime[j];
      ck[now] = 1;
      if (i % prime[j])
        mu[now] = -mu[i];
      else {
        mu[now] = 0;
        break;
      }
    }
  }
}
int t, n, m;
struct node {
  int l, r;
} a[57], aa[57];
long long sum[100007], dp[55][100007];
long long DP(int d) {
  int mm = m / d;
  for (int i = 1; i <= n; i++) {
    aa[i].l = (a[i].l - 1) / d + 1;
    aa[i].r = a[i].r / d;
  }
  sum[0] = 0;
  for (int i = 1; i <= n; i++) {
    if (aa[i].l > aa[i].r) return 0;
    for (int j = 1; j <= mm; j++) {
      if (i == 1 && j >= aa[i].l && j <= aa[i].r)
        dp[i][j] = 1;
      else if (i == 1)
        dp[i][j] = 0;
      else {
        int le = max(0, j - aa[i].r - 1), ri = max(0, j - aa[i].l);
        dp[i][j] = (sum[ri] - sum[le] + mod) % mod;
      }
    }
    for (int j = 1; j <= mm; j++) sum[j] = (sum[j - 1] + dp[i][j]) % mod;
  }
  return sum[mm];
}
int main() {
  t = 1;
  while (t--) {
    scanf("%d%d", &n, &m);
    init();
    for (int i = 1; i <= n; i++) {
      a[i].l = read(), a[i].r = read();
    }
    long long ans = 0;
    for (int d = 1; d <= m; d++) {
      if (!mu[d]) continue;
      ans = (ans + DP(d) * mu[d] + mod) % mod;
    }
    printf("%lld\n", ans);
  }
}
