#include <stdio.h>

int main() {
    int n;
    double sum = 0.0;
    double term = 1.0;

    printf("Enter the value of n: ");
    scanf("%d", &n);

    for (int i = 0; i <= n; i++) {
        sum += term;
        term /= 2;  // each term is 1 / 2^i
    }

    printf("Sum of the series is: %lf\n", sum);

    return 0;
}