func_code_string: #include <bits/stdc++.h>   using namespace std;   const int __ = 1000000;   bool pri[__ + 5];   int num[__ + 5];   void era() {     int x = (int)sqrt(__ + 0.01);     for (int i = 2; i <= x; i++)       if (!pri[i]) {         num[++num[0]] = i;         for (int j = i * i; j <= __; j += i) pri[j] = true;       }     for (int i = x + 1; i <= __; i++)       if (!pri[i]) num[++num[0]] = i;   }   int main() {     era();     int n;     scanf( %d , &n);     int m = n, maxx = 0;     for (int i = 2; i * i <= m; i++)       if (m % i == 0)         for (maxx = i; m % i == 0; m /= i)           ;     if (m != 1) maxx = m;     int x1 = n - maxx + 1, ans = INT_MAX;     for (int i = (1); i <= (num[0]); i++) {       int p = num[i];       int x0 = (x1 + p - 1) / p * p - (p - 1);       int x = (x0 + p - 1) / p * p;       if (x0 > p && x0 >= 3 && x <= n) ans = min(ans, x0);     }     printf( %d n , ans);     return 0;   }   