#include #include #include #include #include #include #include using namespace std; #define REP(i,n) for(int i=0;i<(n);++i) #define FOR(i,a,b) for(int i=(a);i<=(b);++i) typedef long long LL; vector split( const string& s, const string& delim =" " ) { vector res; string t; for ( int i = 0 ; i != s.size() ; i++ ) { if ( delim.find( s[i] ) != string::npos ) { if ( !t.empty() ) { res.push_back( t ); t = ""; } } else { t += s[i]; } } if (!t.empty() ) { res.push_back(t); } return res; } int s2i(string s) { stringstream ss; ss << s; int res; ss >> res; return res; } string i2s(int n) { stringstream ss; ss << n; string res; ss >> res; return res; } int plist[10000],pcount=0; int mm[50000]; int prime(int n){ int i; if ((n!=2&&!(n%2))||(n!=3&&!(n%3))||(n!=5&&!(n%5))||(n!=7&&!(n%7))) return 0; for (i=0;plist[i]*plist[i]<=n;i++) if (!(n%plist[i])) return 0; return n>1; } void initprime(){ int i; mm[2] = 1; for (plist[pcount++]=2,i=3;i<50000;i++) if (prime(i)) { mm[i] = 1; plist[pcount++]=i; } } bool isok(int n) { //cout << "n = " << n << endl; int res = 0; REP(i,pcount) { if (n % plist[i] == 0) { ++res; if (res > 4) return false; while (n % plist[i] == 0) n /= plist[i]; } if (plist[i] * plist[i] > n) { ++res; break; } } //cout << res << endl; return res == 4; } void run() { initprime(); vector mm; for (int i = 647; ; ++i) { if (isok(i)) { mm.push_back(i); cout << "size = " << mm.size() << endl; if (mm.size() == 4) { cout << mm[0] << endl; return; } } else { mm.clear(); } } } int main() { run(); }