1ab

#include <iostream>
using namespace std;
int main()
{
    int m;
    cout << "vvedite m\n";
    cin >> m;
    double sum = 0;
    for(int n = 1; n <= m; n++)
    {
		double f = 1;
		for(int i = 0; i < n; i++)
        	f *= 2;
		double s = 1;
		for(int i = 0; i < n; i++)
        	s *= 3;
        sum += f / s;
    }
    cout << sum;
    return 0;
}