func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long mod = 998244353;   long long sum[55][100005], f[55][100005], t[100005];   int l[55], r[55];   int add(int p, int x, int y) {     if (x < 0) return 0;     if (y < 0) return sum[p][x];     return sum[p][x] - sum[p][y];   }   long long solve1(int n, int m) {     long long ans = 0;     for (int i = l[1]; i <= r[1]; i++) f[1][i] = 1;     for (int i = 1; i <= m; i++) sum[1][i] = (sum[1][i - 1] + f[1][i]) % mod;     for (int i = 2; i <= n; i++) {       for (int j = 1; j <= m; j++) {         f[i][j] = add(i - 1, j - l[i], j - r[i] - 1);         sum[i][j] = (sum[i][j - 1] + f[i][j]) % mod;       }     }     for (int i = 1; i <= m; i++) ans = (ans + f[n][i]) % mod;     for (int i = 1; i <= n; i++)       for (int j = 1; j <= m; j++) f[i][j] = sum[i][j] = 0;     return ans;   }   long long solve2(int n, int m, int d) {     long long ans = 0;     for (int i = d; i <= m; i += d)       if (i >= l[1] && i <= r[1]) f[1][i] = 1;     for (int i = d; i <= m; i += d) sum[1][i] = f[1][i] + sum[1][i - d];     for (int i = 2; i <= n; i++) {       for (int j = d; j <= m; j += d) {         int R = j - l[i] - ((j - l[i]) % d + d) % d;         int L = j - r[i] - ((j - r[i]) % d + d) % d;         if ((j - r[i]) % d == 0) L -= d;         f[i][j] = add(i - 1, R, L);         sum[i][j] = (sum[i][j - d] + f[i][j]) % mod;       }     }     for (int i = d; i <= m; i += d) ans = (ans + f[n][i]) % mod;     for (int i = 1; i <= n; i++)       for (int j = d; j <= m; j += d) f[i][j] = sum[i][j] = 0;     return ans;   }   int main() {     int n, m;     scanf( %d%d , &n, &m);     for (int i = 1; i <= n; i++) scanf( %d%d , &l[i], &r[i]);     long long ans = solve1(n, m);     for (int d = 2; d <= m / n; d++) {       ans = ((ans - (1 - t[d]) * solve2(n, m, d)) % mod + mod) % mod;       for (int j = 2; j * d <= m; j++) t[j * d] += 1 - t[d];     }     printf( %lld , ans);     return 0;   }   