func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 4000010;   long long f[MAXN], sum[MAXN], MOD;   int main() {     int n;     scanf( %d %lld , &n, &MOD);     f[n] = 1;     sum[n] = 1;     for (int i = n - 1; i; --i) {       f[i] = (f[i] + sum[i + 1]) % MOD;       for (int j = 2; j * i <= n; ++j) {         int l = j * i, r = min(n, i * j + j - 1);         f[i] += sum[l] - sum[r + 1];         f[i] = (f[i] % MOD + MOD) % MOD;       }       sum[i] = (sum[i + 1] + f[i]) % MOD;     }     printf( %lld n , f[1]);     return 0;   }   