#include int prime(long long int value) { unsigned int divisor = 3; unsigned int square = divisor * divisor; if (value == 2) return 1; if (value == 3) return 1; if (!(value & 1)) return 0; /* even */ while (square < value && value % divisor) { ++divisor; square += 4 * divisor; ++divisor; } return value % divisor != 0; } int main() { long long int p = 2; int i = 0; while (i < 10001) { if (prime(p)) { i++; } p++; } printf("%d\n",(p-1)); }