#include <iostream>

int main() {
    double p; // Probability of getting a rare character
    std::cout << "Enter the probability of getting a rare character (0 to 1): ";
    std::cin >> p;

    if (p <= 0 || p >= 1) {
        std::cout << "Invalid probability. Please enter a value between 0 and 1." << std::endl;
        return 1;
    }

    double expectedSpins = 1 / p;
    std::cout << "Expected number of spins until a rare character: " << expectedSpins << std::endl;

    return 0;
}