#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define REP(i,s,n) for(int i=(int)(s);i<(int)(n);i++) using namespace std; typedef long long int ll; typedef vector VI; typedef pair PI; const double EPS=1e-9; const int DEBUG = 1; const int N = 200100; int k, n; int a[N]; int bucket[9]; int main(void){ cin >> k >> n; REP(i, 0, N) { a[i] = 1; } a[0] = a[1] = 0; int c = 2; while (c <= n) { if (a[c] == 0) { c++; continue; } REP(i, 2, (N + 1) / c) { a[i * c] = 0; } c++; } int m = 0; int mlen = 0; int i = k, j = k; int cnt = 0; REP(q, 0, 9) { bucket[q] = 0; } while(i <= n) { if(a[i] == 0) { i++; j = max(i, j); continue; } for (;j <= n; ++j) { if (a[j] == 0) { continue; } if (bucket[j % 9]) { break; } cnt++; bucket[j % 9] = 1; } if (mlen <= cnt) { if (DEBUG) { cout << "i=" << i << ", j=" << j << ", cnt=" << cnt << endl; } m = i; mlen = cnt; } bucket[i % 9] = 0; i++; cnt--; } cout << m << endl; }