#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; string i2s(int n) { stringstream ss; ss << n; string res; ss >> res; return res; } LL s2ll(string str) { stringstream ss; ss << str; LL res; ss >> res; return res; } int doit(int n) { int m = 9; for (int i = 1; ; ++i) { if (n <= m * i) { int b = m / 9; int m = (n - 1) / i + b; int d = n % i; if (d == 0) d = i; string s = i2s(m); return s[d - 1] - '0'; } n -= m * i; m *= 10; } return 0; } void run() { int res = 1; int n = 1; while (true) { res *= doit(n); n *= 10; if (n > 1000000) break; } cout << res << endl; } int main() { run(); return 0; }